U.S.-China Strategic Competition in South and East China Seas: Background and Issues for Congress

U.S.-China Strategic Competition in South

and East China Seas: Background and Issues

for Congress

Updated May 1, 2025

Congressional Research Service

https://crsreports.congress.gov

R42784

U.S.-China Strategic Competition in South and East China Seas

Summary

Over the past 15 years, the South China Sea (SCS) has emerged as an arena of strategic

competition between the United States and the People’s Republic of China (PRC, or China).

China’s actions in the SCS—including extensive island-building and base-construction activities

at sites that it occupies in the Spratly Islands, as well as actions by its maritime forces to assert

China’s claims against competing claims by regional neighbors such as the Philippines and

Vietnam—have heightened concerns among U.S. observers that China is gaining effective control

of the SCS, an area of strategic, political, and economic importance to the United States and its

allies and partners. Actions by China’s maritime forces at the Japan-administered Senkaku Islands

in the East China Sea (ECS) are another concern for U.S. observers. PRC domination of China’s

near-seas region—meaning the SCS and ECS, along with the Yellow Sea—could substantially

affect U.S. strategic, political, and economic interests in the Indo-Pacific region and elsewhere.

Potential broader U.S. goals for U.S.-China strategic competition in the SCS and ECS include but

are not necessarily limited to the following: fulfilling U.S. security commitments in the Western

Pacific, including treaty commitments to Japan and the Philippines; maintaining and enhancing

the U.S.-led security architecture in the Western Pacific, including U.S. security relationships

with treaty allies and partner states; maintaining a regional balance of power favorable to the

United States and its allies and partners; defending the principle of peaceful resolution of disputes

and resisting the emergence of an alternative “might-makes-right” approach to international

affairs; defending the principle of freedom of the seas, also sometimes called freedom of

navigation; preventing China from becoming a regional hegemon in East Asia; and pursuing these

goals as part of a larger U.S. strategy for competing strategically and managing relations with

China.

Potential specific U.S. goals for U.S.-China strategic competition in the SCS and ECS include but

are not necessarily limited to the following: dissuading China from carrying out additional baseconstruction activities in the SCS, moving additional military personnel, equipment, and supplies

to bases at sites that it occupies in the SCS, initiating island-building or base-construction

activities at Scarborough Shoal in the SCS, declaring straight baselines around land features it

claims in the SCS, or declaring an air defense identification zone (ADIZ) over the SCS; and

encouraging China to reduce or end operations by its maritime forces at the Senkaku Islands in

the ECS, halt actions intended to put pressure against Philippine-occupied sites in the Spratly

Islands, provide greater access by Philippine fisherman to waters surrounding Scarborough Shoal

or in the Spratly Islands, adopt the U.S./Western definition regarding freedom of the seas, and

accept and abide by the July 2016 tribunal award in the SCS arbitration case involving the

Philippines and China.

The issue for Congress is whether the Administration’s strategy for competing strategically with

China in the SCS and ECS is appropriate and correctly resourced, and whether Congress should

approve, reject, or modify the strategy, the level of resources for implementing it, or both.

Decisions that Congress makes on these issues could substantially affect U.S. strategic, political,

and economic interests in the Indo-Pacific region and elsewhere.

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Contents

Introduction ..................................................................................................................................... 1

Background ..................................................................................................................................... 1

U.S. Interests in SCS and ECS .................................................................................................. 1

Overview ............................................................................................................................. 1

Specific Elements................................................................................................................ 1

Maritime Territorial and EEZ Disputes Involving China .......................................................... 7

Maritime Territorial Disputes.............................................................................................. 7

EEZ Dispute ........................................................................................................................ 8

Relationship of Maritime Territorial Disputes to EEZ Dispute .......................................... 8

China’s Approach to SCS and ECS ........................................................................................... 9

Overview ............................................................................................................................. 9

Selected Elements ............................................................................................................. 10

Assessments of China’s Strengthened Position in SCS .................................................... 16

U.S. Position Regarding Issues Relating to SCS and ECS ..................................................... 17

Overview ........................................................................................................................... 17

Freedom of Navigation (FON) Program ........................................................................... 19

Taiwan Strait Transits ....................................................................................................... 20

Issues for Congress ........................................................................................................................ 21

U.S. Strategy for Competing Strategically with China in SCS and ECS ................................ 21

Overview ........................................................................................................................... 21

U.S. Strategy During First Trump Administration ............................................................ 27

U.S. Strategy During Biden Administration ..................................................................... 29

Assessing U.S. Strategy .................................................................................................... 31

Risk of Incident, Crisis, or Conflict Involving U.S. Forces .................................................... 32

Risk Relating to U.S. and PRC Military Operations In SCS ............................................ 32

Risk Relating to Maritime Territorial Disputes Involving Allies ...................................... 32

Whether United States Should Ratify UNCLOS .................................................................... 33

Legislative Activity in the 118th Congress ..................................................................................... 35

Legislative Activity for FY2025 ............................................................................................. 35

FY2025 National Defense Authorization Act (NDAA) (H.R. 8070/S. 4638/H.R.

5009 /P.L. 118-159)........................................................................................................ 35

Other Legislative Activity ....................................................................................................... 35

Introduced in House .......................................................................................................... 35

Introduced in Senate ......................................................................................................... 36

Figures

Figure 1. Reported Military Facilities at SCS Sites Occupied by China ....................................... 15

Figure 2. Reported PRC Aircraft, Missile, and Radar Ranges ...................................................... 16

Figure A-1. Maritime Territorial Disputes Involving China .......................................................... 38

Figure A-2. Locations of 2001, 2002, and 2009 U.S.-PRC Incidents at Sea and In Air ............... 41

Figure E-1. Map of the Nine-Dash Line ........................................................................................ 71

Figure E-2. EEZs Overlapping Zone Enclosed by Map of Nine-Dash Line ................................. 72

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Figure G-1. EEZs in South China Sea and East China Sea ........................................................... 94

Figure G-2. Claimable World EEZs .............................................................................................. 95

Tables

Table 1. China’s Apparent Goals and Supporting Actions for South China Sea ........................... 10

Appendixes

Appendix A. Maritime Territorial and EEZ Disputes in SCS and ECS ........................................ 37

Appendix B. U.S. Security Treaties with Japan and Philippines ................................................... 45

Appendix C. Treaties and Agreements Related to the Maritime Disputes .................................... 47

Appendix D. July 2016 Tribunal Award in Philippines-China SCS Arbitration Case ................... 57

Appendix E. China’s Approach to Maritime Disputes in SCS and ECS ....................................... 61

Appendix F. Assessments of China’s Strengthened Position in SCS ............................................ 81

Appendix G. U.S. Position Regarding SCS, ECS, and EEZ Operational Rights .......................... 84

Appendix H. U.S. Freedom of Navigation (FON) Program .......................................................... 99

Appendix I. Writings by Observers Regarding U.S. Strategy for SCS and ECS ........................ 105

Contacts

Author Information....................................................................................................................... 111

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U.S.-China Strategic Competition in South and East China Seas

Introduction

This report provides background information and issues for Congress regarding strategic

competition between the United States and the People’s Republic of China (PRC, or China) in the

South China Sea (SCS) and East China Sea (ECS). Over the past 15 years, the SCS has emerged

as an arena of U.S.-China strategic competition.1 China’s actions in the SCS have heightened

concerns among U.S. observers that China is gaining effective control of the SCS, an area of

strategic, political, and economic importance to the United States and its allies and partners.

Actions by China’s maritime forces at the Japan-administered Senkaku Islands in the ECS are

another concern for U.S. observers. PRC domination of China’s near-seas region—meaning the

SCS, ECS, and Yellow Sea—could substantially affect U.S. strategic, political, and economic

interests in the Indo-Pacific region and elsewhere.

The issue for Congress is whether the Administration’s strategy for competing strategically with

China in the SCS and ECS is appropriate and correctly resourced, and whether Congress should

approve, reject, or modify the strategy, the level of resources for implementing it, or both.

Decisions that Congress makes on these issues could substantially affect U.S. strategic, political,

and economic interests in the Indo-Pacific region and elsewhere.

For a brief overview of maritime territorial disputes in the SCS and ECS that involve China, see

“Maritime Territorial Disputes,” below, and Appendix A. Other CRS reports provide additional

and more detailed information on these disputes.2

Background

U.S. Interests in SCS and ECS

Overview

Although disputes in the SCS and ECS involving China and its neighbors may appear at first

glance to be disputes between faraway countries over a few rocks and reefs in the ocean that are

of seemingly little importance to the United States, the SCS and ECS can engage U.S. interests

for a variety of strategic, political, and economic reasons, including but not necessarily limited to

those discussed in the sections below.

Specific Elements

U.S. Regional Allies and Partners, and U.S. Regional Security Architecture

The SCS, ECS, and Yellow Sea border three U.S. treaty allies: Japan, South Korea, and the

Philippines. (For additional information on the U.S. security treaties with Japan the Philippines,

see Appendix B.) In addition, the SCS and ECS (including the Taiwan Strait) surround Taiwan,

1 For more on U.S. strategic competition with China and Russia, also known as great power competition, see CRS

Report R43838, Great Power Competition: Implications for Defense—Issues for Congress, by Ronald O'Rourke.

2 See CRS In Focus IF10607, China Primer: South China Sea Disputes, by Ben Dolven, Caitlin Campbell, and Ronald

O'Rourke; CRS In Focus IF12550, China-Philippines Tensions in the South China Sea, by Caitlin Campbell, Ben

Dolven, and William Piekos; CRS Report R44072, Chinese Land Reclamation in the South China Sea: Implications

and Policy Options, by Ben Dolven et al.; CRS Report R42930, Maritime Territorial Disputes in East Asia: Issues for

Congress, by Ben Dolven, Mark E. Manyin, and Shirley A. Kan; and CRS Report R43894, China's Air Defense

Identification Zone (ADIZ), by Ian E. Rinehart and Bart Elias.

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regarding which the United States has certain security-related policies under the Taiwan Relations

Act (H.R. 2479/P.L. 96-8 of April 10, 1979),3 and the SCS borders Southeast Asian nations that

are current, emerging, or potential U.S. partner countries, such as Singapore, Vietnam, and

Indonesia.

In a conflict with the United States, PRC bases in the SCS and forces operating from them4 would

add to a network of PRC anti-access/area-denial (A2/AD) capabilities intended to keep U.S.

military forces outside the first island chain (and thus away from China’s mainland and Taiwan).5

PRC bases in the SCS and forces operating from them could also help create a bastion (i.e., a

defended operating sanctuary) in the SCS for China’s emerging sea-based strategic deterrent force

of nuclear-powered ballistic missile submarines (SSBNs).6 In a conflict with the United States,

PRC bases in the SCS and forces operating from them would be vulnerable to U.S. attack.

Attacking the bases and the forces operating from them, however, would tie down the attacking

U.S. forces for a time at least, delaying the use of those U.S. forces elsewhere in a larger conflict,

and potentially delay the advance of U.S. forces into the SCS.

Short of a conflict with the United States, PRC bases in the SCS, and more generally, PRC

domination over or control of its near-seas region could help China to do one or more of the

following on a day-to-day basis:

•

•

•

•

•

control fishing operations, oil and gas exploration activities, seabed mining, and

seabed internet cable-laying operations7 in the SCS—a body of water with an

area more than twice that of the Mediterranean Sea;8

coerce, intimidate, or put political pressure on other countries bordering on the

SCS;

announce and enforce an air defense identification zone (ADIZ) over the SCS;

announce and enforce a maritime exclusion zone (i.e., a blockade) around

Taiwan;

facilitate the projection of PRC military presence and political influence further

into the Western Pacific; and

3 For more on the Taiwan Relations Act, see CRS In Focus IF10275, Taiwan: Background and U.S. Relations, by

Susan V. Lawrence; and CRS In Focus IF12481, Taiwan: Defense and Military Issues, by Caitlin Campbell.

4 For an overview of some of the A2/AD capabilities that China has built on sites that it occupies in the SCS, see J.

Michael Dahm, Introduction to South China Sea Military Capability Studies, Johns Hopkins Applied Physics

Laboratory, July 2020, 17 pp. See also Zachary Haver (Insikt Group), The People's Liberation Army in the South China

Sea: An Organizational Guide, Recorded Future, January 19, 2022, 32 pp.

5 The term first island chain refers to a string of islands, including Japan and the Philippines, that encloses China’s

near-seas region. The term second island chain, which reaches out to Guam, refers to a line that can be drawn that

encloses both China’s near-seas region and the Philippine Sea between the Philippines and Guam. For a map of the first

and second island chains, see Department of Defense, Military and Security Developments Involving the People’s

Republic of China 2024, Annual Report to Congress, released on December 18, 2024, p. 67. The exact position and

shape of the lines demarcating the first and second island chains often differ from map to map.

6 See, for example, Felix K. Chang, “China’s Maritime Intelligence, Surveillance, and Reconnaissance Capability in the

South China Sea,” Foreign Policy Research Institute, May 5, 2021.

7 Regarding seabed internet cable-laying operations, see, for example, Anna Gross, Alexandra Heal, Demetri

Sevastopulo, Kathrin Hille, and Mercedes Ruehl, “China Exerts Control over Internet Cable Projects in South China

Sea,” Financial Times, March 13 2023.

8 The National Oceanic and Atmospheric Administration (NOAA) states that the area of the South China Sea is 6.963

million square kilometers (about 2.688 million square miles)—more than twice that of the Mediterranean Sea, which is

2.967 million square kilometers (about 1.146 million square miles). (National Oceanic and Atmospheric

Administration, National Geophysical Data Center, “World Ocean Volumes,” accessed April 30, 2025, at

https://www.ncei.noaa.gov/sites/g/files/anmtlf171/files/2023-01/World%20Ocean%20Volumes.pdf.)

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•

help achieve a broader goal of becoming a regional hegemon in its part of

Eurasia.

In light of some of the preceding points, PRC bases in the SCS, and more generally, PRC

domination over or control of its near-seas region could complicate the ability of the United

States to

•

•

•

•

intervene militarily in a crisis or conflict between the People’s Republic of China

and Taiwan;

fulfill U.S. obligations under U.S. defense treaties with Japan and the Philippines

and South Korea;

operate U.S. forces in the Western Pacific for various purposes, including

maintaining regional stability, conducting engagement and partnership-building

operations, responding to crises, and executing war plans; and

prevent the emergence of China as a regional hegemon in its part of Eurasia.

A reduced U.S. ability to do one or more of the above could encourage countries in the region to

reexamine their own defense programs and foreign policies, potentially leading to a further

change in the region’s security architecture that might not be in the U.S. interest. Some observers

believe that China is trying to use disputes in the SCS and ECS to raise doubts among U.S. allies

and partners in the region about the dependability of the United States as an ally or partner, or to

otherwise drive a wedge between the United States and its regional allies and partners, so as to

weaken the U.S.-led regional security architecture and thereby facilitate greater PRC influence

over the region.

Some observers remain concerned that maritime territorial disputes in the ECS and SCS could

lead to a crisis or conflict between China and a neighboring country such as the Philippines or

Japan, and that the United States could be drawn into such a crisis or conflict as a result of

obligations the United States has under bilateral security treaties with the Philippines and Japan.

Principle of Nonuse of Force or Coercion

A key element of the international order that the United States and its allies established in the

years after World War II9 is the principle that force or coercion should not be used as a means of

settling disputes between countries, and certainly not as a routine or first-resort method. Some

observers are concerned that China’s actions in SCS and ECS challenge this principle and—along

with Russia’s war against Ukraine—could help reestablish the very different principle of “might

makes right” (i.e., the law of the jungle) as a routine or defining characteristic of international

relations.10

Principle of Freedom of the Seas

Another key element of the post-World War II international order is the principle of freedom of

the seas, meaning the treatment of the world’s seas under international law as international waters

9 For more on international order that the United States and its allies established in the years after World War II, see the

section entitled “Defense and Promotion of Liberal International Order” in CRS Report R44891, U.S. Role in the

World: Background and Issues for Congress, by Ronald O'Rourke.

10 See, for example, Dan Lamothe, “Navy Admiral Warns of Growing Sense That ‘Might Makes Right’ in Southeast

Asia,” Washington Post, March 16, 2016. Related terms and concepts include the law of the jungle or the quotation

from the Melian Dialogue in Thucydides’ History of the Peloponnesian War that “the strong do what they can and the

weak suffer what they must.”

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(i.e., as a global commons), and freedom of operations in international waters. Freedom of the

seas is sometimes referred to as freedom of navigation, although the term freedom of navigation

is sometimes defined—particularly by parties who might not support freedom of the seas—in a

narrow fashion, to include merely the freedom for commercial ships to pass through sea areas, as

opposed to the freedom for both civilian and military ships and aircraft to conduct various

activities at sea or in the airspace above. A more complete way to refer to the principle of freedom

of the seas, as stated in the Department of Defense’s (DOD’s) annual Freedom of Navigation

(FON) report, is “all of the rights, freedoms, and uses of the sea and airspace guaranteed to all

nations by international law.”11 DOD stated in 2015 that freedom of the seas

includes more than the mere freedom of commercial vessels to transit through international

waterways. While not a defined term under international law, the Department uses

“freedom of the seas” to mean all of the rights, freedoms, and lawful uses of the sea and

airspace, including for military ships and aircraft, recognized under international law.

Freedom of the seas is thus also essential to ensure access in the event of a crisis. 12

The principle of freedom of the seas dates back about 400 years, to the early 1600s,13 and is

reflected in the United Nations Convention on the Law of the Sea (UNCLOS), Article 89 of

which states, “No State may validly purport to subject any part of the high seas to its

sovereignty.” The principle of freedom of the seas has long been a matter of importance to the

United States. DOD stated in 2018 that

Throughout its history, the United States has asserted a key national interest in preserving

the freedom of the seas, often calling on its military forces to protect that interest.

Following independence, one of the U.S. Navy’s first missions was to defend U.S.

commercial vessels in the Atlantic Ocean and Mediterranean Sea from pirates and other

maritime threats. The United States went to war in 1812, in part, to defend its citizens’

rights to commerce on the seas. In 1918, President Woodrow Wilson named “absolute

freedom of navigation upon the seas” as one of the universal principles for which the

United States and other nations were fighting World War I. Similarly, before World War

II, President Franklin Roosevelt declared that our military forces had a “duty of

maintaining the American policy of freedom of the seas.” 14

DOD similarly stated in 2019 that

Since its founding, the United States has stood for—and fought for—freedom of the seas.

As a result of that commitment, freedom of navigation has been enshrined as a fundamental

tenet of the rules-based international order for the last 75 years. In that time, it has proved

essential to global security and stability and the prosperity of all nations.15

11 Department of Defense, Department of Defense Report to Congress, Annual Freedom of Navigation Report, Fiscal

Year 2023, generated on March 8, 2024, released on May 8, 2024, PDF page 3 of 6.

12

Department of Defense, Asia-Pacific Maritime Security Strategy, undated but released August 2015, p. 2.

13 The idea that most of the world’s seas should be treated as international waters rather than as a space that could be

appropriated as national territory dates back to Hugo Grotius (1583-1645), a founder of international law, whose 1609

book Mare Liberum (“The Free Sea”) helped to establish the primacy of the idea over the competing idea, put forth by

the legal jurist and scholar John Seldon (1584-1654) in his book 1635 book Mare Clausum (“Closed Sea”), that the sea

could be appropriated as national territory, like the land. For further discussion, see “Hugo Grotius’ ‘Mare Liberum’—

400th Anniversary,” International Law Observer, March 10, 2009.

14 Department of Defense, Department of Defense Report to Congress, Annual Freedom of Navigation Report, Fiscal

Year 2018, Pursuant to Section 1275 of the National Defense Authorization Act for Fiscal Year 2018, December 31,

2018 (generated February 28, 2019), p. 1.

15 Department of Defense, Department of Defense Report to Congress, Annual Freedom of Navigation Report, Fiscal

Year 2019, Pursuant to Section 1275 of the National Defense Authorization Act for Fiscal Year (FY) 2017 (P.L. 114(continued...)

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Some observers are concerned that China’s interpretation of law of the sea and its actions in the

SCS pose a significant challenge to the principle of freedom of the seas. Matters of particular

concern in this regard include China’s so-called nine-dash map of the SCS, China’s apparent

narrow definition of freedom of navigation, and China’s position that coastal states have the right

to regulate the activities of foreign military forces in their exclusive economic zones (EEZs) (see

“China’s Approach to SCS and ECS,” below, and Appendix A and Appendix E).16

Observers are concerned that a challenge to freedom of the seas in the SCS could have

implications for the United States not only in the SCS, but around the world, because

international law is universal in application, and a challenge to a principle of international law in

one part of the world, if accepted, could serve as a precedent for challenging it in other parts of

the world. In general, limiting or weakening the principle of freedom of the seas could represent a

departure or retreat from the roughly 400-year legal tradition of treating the world’s oceans as

international waters (i.e., as a global commons) and as a consequence alter the international legal

regime governing sovereignty over much of the surface of the world.17

More specifically, if China’s position on the issue of whether coastal states have the right to

regulate the activities of foreign military forces in their EEZs were to gain greater international

acceptance under international law, it could substantially affect U.S. naval operations not only in

the SCS, but around the world, which in turn could substantially affect the ability of the United

States to use its military forces to defend various U.S. interests overseas. Significant portions of

the world’s oceans are claimable as EEZs, including high-priority U.S. Navy operating areas in

the Western Pacific, the Persian Gulf, and the Mediterranean Sea.18 The legal right of U.S. naval

forces to operate freely in EEZ waters—an application of the principle of freedom of the seas—is

important to their ability to perform many of their missions around the world, because many of

those missions are aimed at influencing events ashore, and having to conduct operations from

328), generated February 28, 2020, p. 1. DOD similarly stated in 2019 in another document that

Throughout our history, the United States has asserted a key national interest in preserving the

freedom of the seas, and has often relied on the U.S. military forces to protect that interest. As

President Ronald Reagan said in releasing the U.S. Oceans Policy in 1983, “we will not acquiesce

in unilateral actions of other states designed to restrict the rights and freedoms of the international

community in navigation and overflight.”

(Department of Defense, Indo-Pacific Strategy Report, Preparedness, Partnerships, and Promoting

a Networked Region, June 1, 2019, p. 43.)

16 A country’s EEZ includes waters extending up to 200 nautical miles from its land territory. EEZs were established as

a feature of international law by United Nations Convention on the Law of the Sea (UNCLOS). Coastal states have the

right UNCLOS to regulate foreign economic activities in their own EEZs.

17 See, for example, Karishma Vaswani, “How China Is Rewriting the Law of the Sea,” Bloomberg, February 23, 2025;

Elisabeth Braw, “From Russia’s Shadow Fleet to China’s Maritime Claims: The Freedom of the Seas Is Under Threat,”

Atlantic Council, January 23, 2025; David Bosco, “China is Reshaping the Maritime Legal Order,” Lawfare, July 25,

2024 (a book review of China’s Law of the Sea: The New Rules of Maritime Order, by Isaac B. Kardon); Peter A.

Dutton, “China Is Rewriting the Law of the Sea,” Foreign Policy, June 10, 2023; James Stavridis, “Russia-U.K.

Standoff Shows the New War at Sea Has Gone Global,” Bloomberg, July 2, 2021; James Holmes, “Do Russia Or China

Have ‘Limited’ Or ‘Unlimited’ Political Goals?” 19FortyFive, April 4, 2021; Malcolm Jorgensen, “China Is

Overturning the Rules-Based Order from Within,” Interpreter, August 12, 2020; James Holmes, “China Wants

Ownership of the South China Sea. Here’s Why That Can’t Happen,” National Interest, July 17, 2020; Lyle J.

Goldstein, “China Studies the Contours of the Gray Zone; Beijing Strategists Go to School on Russian Tactics in the

Black Sea,” National Interest, August 27, 2019; Roncevert Ganan Almond, “The Extraterrestrial [Legal] Impact of the

South China Sea Dispute,” The Diplomat, October 3, 2017.

18 The National Oceanic and Atmospheric Administration (NOAA) calculates that EEZs account for about 30.4% of the

world’s oceans. (See “Comparative Sizes of the Various Maritime Zones” at the end of “Maritime Zones and

Boundaries,” accessed April 30, 2025, at https://www.noaa.gov/maritime-zones-and-boundaries, which states that

EEZs account for 101.9 million square kilometers of the world’s approximately 335.0 million square kilometers of

oceans.)

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outside a country’s EEZ (i.e., more than 200 miles offshore) would reduce the inland reach and

responsiveness of U.S. ship-based sensors, aircraft, and missiles, and make it more difficult for

the United States to transport Marines and their equipment from ship to shore. Restrictions on the

ability of U.S. naval forces to operate in EEZ waters could potentially require changes (possibly

very significant ones) in U.S. military strategy, U.S. foreign policy goals, or U.S. grand strategy.19

Trade Routes and Hydrocarbons

Major commercial shipping routes pass through the SCS, which links the Western Pacific to the

Indian Ocean and Persian Gulf. One source estimated that, as of 2016, about $3.4 trillion worth of

international shipping trade passed through the SCS each year. This same source states

The United Nations Conference on Trade and Development (UNCTAD) estimates that

roughly 80 percent of global trade by volume and 70 percent by value is transported by

sea. Of that volume, 60 percent of maritime trade passes through Asia, with the South

China Sea carrying an estimated one-third of global shipping. Its waters are particularly

critical for China, Taiwan, Japan, and South Korea, all of which rely on the Strait of

Malacca, which connects the South China Sea and, by extension, the Pacific Ocean with

the Indian Ocean.20

DOD similarly states that the SCS “plays an important role in security considerations across East

Asia because of the region’s reliance on the flow of oil and commerce through SCS shipping

lanes, including more than 80% of the crude oil [flowing] to the PRC, Japan, South Korea, and

Taiwan.”21 In addition, the ECS and SCS contain potentially significant oil and gas exploration

areas.22

19 See, for example, United States Senate, Committee on Foreign Relations, Committee on Foreign Relations, Hearing

on Maritime Disputes and Sovereignty Issues in East Asia, July 15, 2009, Testimony of Peter Dutton, Associate

Professor, China Maritime Studies Institute, U.S. Naval War College, pp. 2 and 6-7.

20 “How Much Trade Transits the South China Sea?” China Power (CSIS), August 2, 2017, updated January 25, 2021,

accessed April 30, 2025, at https://chinapower.csis.org/much-trade-transits-south-china-sea/. See also Kerem Coşar and

Benjamin D. Thomas, “The Geopolitics of International Trade in Southeast Asia,” working paper, National Bureau of

Economic Research, November 2020, 17 pp., accessed April 30, 2025, at https://www.nber.org/papers/w28048.

21 Department of Defense, Military and Security Developments Involving the People’s Republic of China 2024, Annual

Report to Congress, released December 18, 2024, p. 18.

22 See, for example, International Institute for Strategic Studies, The Economic and Security Implications of China’s

Activities in the South China Sea, November 2021, 3 pp. See also Christian Edwards, “The South China Sea Is Fabled

for Its Hidden Energy Reserves and China Wants to Block Outsiders Like the US from Finding Them,” Business

Insider, November 13, 2018.

For contrary views regarding the importance of the SCS in connection with trade routes and hydrocarbons, see John

Quiggin, “Myths That Stir Trouble in the South China Sea, A Major Shipping Route, Yes, But Vital? False Claims

About the Value of These Waters Only Make Diplomacy Harder,” Interpreter, December 23, 2021; Ethen Kim Lieser,

“How Much Oil and Gas Is Contained in the South China Sea? The Entire Contested Region Is Chock-Full Of

Valuable Resources. Or Is It?” National Interest, February 22, 2021; Marshall Hoyler, “The South China Sea Is

Overrated, Assigning the South China Sea Geostrategic Importance Based on Its Popular Sea Lanes or Assumed Oil

and Gas Reserves Is Suspect,” U.S. Naval Institute Proceedings, June 2019. See also Mark Crescenzi and Stephen

Gent, “China’s Deep-Sea Motivation for Claiming Sovereignty Over the South China Sea, At the Bottom of the

Contested Waters Lies a Supply of the Rare Earth Minerals Crucial to China’s Tech Ambitions,” Diplomat, May 6,

2021.

The SCS and ECS also contain significant fishing grounds that are of interest primarily to China and other countries in

the region. See, for example, Michael Perry, “Cooperative Maritime Law Enforcement and Overfishing in the South

China Sea,” Center for International Maritime Security (CIMSEC), April 6, 2020; James G. Stavridis and Johan

Bergenas, “The Fishing Wars Are Coming,” Washington Post, September 13, 2017; Keith Johnson, “Fishing Disputes

Could Spark a South China Sea Crisis,” Foreign Policy, April 7, 2012.

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Interpreting China’s Role as a Major World Power

China’s actions in the SCS and ECS could influence assessments that U.S. and other observers

make about China’s role as a major world power, particularly regarding China’s approach to

settling disputes between states (including whether China views force and coercion as acceptable

means for settling such disputes, and consequently whether China believes that “might makes

right”), China’s views toward the meaning and application of international law, and whether

China views itself more as a stakeholder and defender of the current international order, or

alternatively, more as a revisionist power that will seek to change elements of that order that it

does not like.23

U.S.-China Relations in General

Developments in the SCS and ECS could affect U.S.-China relations in general, which could

have implications for other issues in U.S.-China relations.24

Maritime Territorial and EEZ Disputes Involving China

This section provides a brief overview of maritime territorial and EEZ disputes involving China.

For additional details on these disputes (including maps), see Appendix A. In addition, other

CRS reports provide additional and more detailed information on the maritime territorial

disputes.25 For background information on treaties and international agreements related to the

disputes, see Appendix C. For background information on a July 2016 international tribunal

award in an SCS arbitration case involving the Philippines and China, see Appendix D.

Maritime Territorial Disputes

China is a party to multiple maritime territorial disputes in the SCS and ECS, including in

particular the following:

•

•

•

•

a dispute over the Spratly Islands in the SCS, which are claimed entirely by

China, Taiwan, and Vietnam, and in part by the Philippines, Malaysia, Brunei,

and which are occupied in part by all these countries except Brunei;

a dispute over Scarborough Shoal in the SCS, which is claimed by China,

Taiwan, and the Philippines, and controlled since 2012 by China;

a dispute over the Paracel Islands in the SCS, which are claimed by China and

Vietnam, and occupied by China; and

a dispute over the Senkaku Islands in the ECS, which are claimed by China,

Taiwan, and Japan, and administered by Japan.

23 See, for example, Charlie Dunlap, “CDR Tracy Reynolds on ‘China & the Moon & the Law,’” Lawfire, January 23,

2023; Akshobh Giridharadas, “The South China Sea Reveals China’s Grand Strategy, To Understand China’s Grand

Strategy, Particularly Xi’s Long-Term Game, One Needs to Understand Beijing’s Belligerence in the South China

Sea,” National Interest, July 1, 2021.

24 For an overview U.S.-China relations, see CRS In Focus IF10119, China Primer: U.S.-China Relations, by Susan V.

Lawrence and Karen M. Sutter. Additional CRS reports discuss specific issues bearing on U.S.-China relations.

25 See CRS In Focus IF10607, China Primer: South China Sea Disputes, by Ben Dolven, Caitlin Campbell, and Ronald

O'Rourke; CRS In Focus IF12550, China-Philippines Tensions in the South China Sea, by Caitlin Campbell, Ben

Dolven, and William Piekos; CRS Report R44072, Chinese Land Reclamation in the South China Sea: Implications

and Policy Options, by Ben Dolven et al.; CRS Report R42930, Maritime Territorial Disputes in East Asia: Issues for

Congress, by Ben Dolven, Mark E. Manyin, and Shirley A. Kan; and CRS Report R43894, China's Air Defense

Identification Zone (ADIZ), by Ian E. Rinehart and Bart Elias.

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U.S.-China Strategic Competition in South and East China Seas

EEZ Dispute26

In addition to maritime territorial disputes in the SCS and ECS, China is involved in a dispute,

principally with the United States, over whether China has a right under international law to

regulate the activities of foreign military forces operating within China’s EEZ.

The position of the United States and most other countries is that while the United Nations

Convention on the Law of the Sea (UNCLOS), which established EEZs as a feature of

international law, gives coastal states the right to regulate economic activities (such as fishing and

oil exploration) within their EEZs, it does not give coastal states the right to regulate foreign

military activities in the parts of their EEZs beyond their 12-nautical-mile territorial waters.27

The position of China and some other countries (i.e., a minority group among the world’s nations)

is that UNCLOS gives coastal states the right to regulate not only economic activities, but also

foreign military activities, in their EEZs.

The dispute over whether China has a right under UNCLOS to regulate the activities of foreign

military forces operating within its EEZ appears to be at the heart of incidents between PRC and

U.S. ships and aircraft in international waters and airspace dating back at least to 2001.

Relationship of Maritime Territorial Disputes to EEZ Dispute

The issue of whether China has the right under UNCLOS to regulate foreign military activities in

its EEZ is related to, but ultimately separate from, the issue of territorial disputes in the SCS and

ECS:

•

•

The two issues are related because China can claim EEZs from inhabitable

islands over which it has sovereignty, so accepting China’s claims to sovereignty

over inhabitable islands in the SCS or ECS could permit China to expand the

EEZ zone within which China claims a right to regulate foreign military

activities.

The two issues are ultimately separate from one another because even if all the

territorial disputes in the SCS and ECS were resolved, and none of China’s

claims in the SCS and ECS were accepted, China could continue to apply its

concept of its EEZ rights to the EEZ that it unequivocally derives from its

mainland coast—and it is in this unequivocal PRC EEZ that several of the past

U.S.-PRC incidents at sea have occurred.

From the U.S. perspective, the EEZ dispute is arguably as significant as the maritime territorial

disputes because of the EEZ dispute’s proven history of leading to U.S.-PRC incidents at sea and

because of its potential for affecting U.S. military operations not only in the SCS and ECS, but

around the world.

26 In this report, the term EEZ dispute is used to refer to a dispute principally between China and the United States over

whether coastal states have a right under international law to regulate the activities of foreign military forces operating

in their EEZs. There are also other kinds of EEZ disputes, including disputes between neighboring countries regarding

the extents of their adjacent EEZs.

27 The legal term under UNCLOS for territorial waters is territorial seas. This report uses the more colloquial term

territorial waters to avoid confusion with terms like South China Sea and East China Sea.

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China’s Approach to SCS and ECS

Overview

China’s approach to maritime disputes in the SCS and ECS, and to strengthening its position over

time in the SCS, can be characterized as including the following, some of which are discussed

further in following sections:

•

•

•

•

•

•

•

China appears to have identified the assertion and defense of its maritime

territorial claims in the SCS and ECS, and the strengthening of its position in the

SCS, as important national goals.

To achieve these goals, China appears to be employing a multielement strategy

that includes diplomatic, informational, economic, military, paramilitary/law

enforcement, and civilian elements.

China’s approach includes the use of gradualist, “salami-slicing” activities and

gray zone operations, many of which are carried out by China’s maritime militia.

China’s approach includes an apparent preference for discussing maritime

territorial disputes with other countries in the region though bilateral (as opposed

to multilateral) engagements. As the largest country in the region, China may

believe that it can more easily gain the upper hand in bilateral rather than

multilateral discussions, particularly since multilateral discussions can provide

settings for other countries in the region to act collectively to oppose China’s

actions in the SCS and ECS.

China’s approach includes resisting and objecting to the involvement of outside

actors, such as the United States, in maritime disputes in the SCS and ECS, and

discouraging other countries in the region from working collectively with outside

actors such as the United States to oppose China’s actions in the SCS and ECS.

In implementing its approach to maritime disputes in the SCS and ECS, China

appears to be persistent, patient, and tactically flexible—it is “playing a long

game.”

To achieve its goals in the SCS and ECS, China is willing to expend significant

resources and absorb at least some amount of reputational and other costs that

other countries might seek to impose on China in response to China’s actions.28

Table 1 summarizes China’s apparent goals relating to the SCS, and the types of actions it

undertakes in support of those goals, as assessed in a January 2020 report by the Center for a New

American Security (CNAS) on China’s strategy for the SCS.

28 For additional discussion, see Shuxian Luo, “The Rising Power’s Audiences and Cost Trade-offs: Explaining

China’s Escalation and Deescalation in Maritime Disputes,” Asian Security, published online December 21, 2021, at

https://doi.org/10.1080/14799855.2021.2012159; Patrick M. Cronin and Ryan Neuhard, Total Competition, China’s

Challenge in the South China Sea, Center for a New American Security, January 2020, pp. 5-28; Denny Roy, “How

China Is Slow Conquering the South China Sea,” National Interest, May 7, 2020; and Kerry K. Gershaneck, “China’s

‘Political Warfare’ Aims at South China Sea,” Asia Times, July 3, 2018.

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Table 1. China’s Apparent Goals and Supporting Actions for South China Sea

As assessed in January 2020 CNAS report

Apparent goals

Rally support

domestically

Deter

U.S.

Intimidate

neighbors and

encourage

appeasement/

compliance

PLA operationsa

X

X

X

China Coast Guard operationsb

X

X

X

Supporting actions

Maritime militia swarming

Dredging fleet and island

construction team operationsc

Reinforce

image of

China as an

economic

powerhouse

X

X

X

X

X

X

Operations by state banks and

state-owned enterprisesd

State media operationse

Tempt neighbors

to cooperate in

exchange for

future economic

benefits

X

X

X

Source: Adapted by CRS from table on page 20 of Patrick M. Cronin and Ryan Neuhard, Total Competition,

China’s Challenge in the South China Sea, Center for a New American Security, January 2020.

a. Includes military exercises, weapons tests, port visits, patrols throughout the SCS, military parades, and

participation in echelon formation.

b. Includes deployment of large vessels and participation in echelon formation.

c. Includes large-scale dredging and island building, and construction of permanent facilities on disputed

features.

d. Highly visible economic projects around the region, such as bridges, ports, and rail lines.

e. Includes propaganda about the PLA, China’s influence (including its military and economic might and its

political importance), U.S. decline or weakness, and other states conceding to China’s preferences.

A December 13, 2023, opinion piece states that a possible additional goal for China’s actions in

the SCS is to discourage Western businesses from shifting their operations from China to the

Philippines or other countries in the region as part of a friendshoring strategy for reducing

Western reliance on business operations based in China.29

Selected Elements

“Salami-Slicing” Strategy and Gray Zone Operations

Observers frequently characterize China’s approach to the SCS and ECS as a gradualist, “salamislicing” strategy that employs a series of incremental actions, none of which by itself is a casus

belli, to gradually change the status quo in China’s favor.30 Other observers have referred to this

29 Elisabeth Braw, “Why China Is Stepping Up Its Maritime Attacks on the Philippines,” Foreign Policy, December 13,

2023.

30 See, for example, Atul Kumar, Challenges to China’s ‘Below the Threshold’ Military Strategy in Its Near Seas,

Observer Research Foundation (ORF), April 2025 (published online April 7, 2025), 29 pp.; Julian Ryall, “As Regional

Tensions Rise, China Probing Neighbors’ Defense,” Deutsche Welle (DW), October 13, 2022. Another press report

refers to the process as “akin to peeling an onion, slowly and deliberately pulling back layers to reach a goal at the

center.” (Brad Lendon, “China Is Relentlessly Trying to Peel away Japan’s Resolve on Disputed Islands,” CNN, July 8,

2022.)

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approach as incrementalism,31 creeping annexation,32 creeping invasion,33 or working to gain

ownership through adverse possession,34 or as a “talk and take” strategy, meaning a strategy in

which China engages in (or draws out) negotiations while taking gradual actions to gain control

of contested areas.35

Observers argue that in support of this gradualist approach, China makes frequent use of gray

zone operations, meaning operations that reside in a gray zone between peace and war.36 Gray

zone operations can create a conundrum for countries that seek ways to counter them effectively

without appearing to employ excessive force or risk escalating the level of violence. Some

observers argue that rather than using the term gray zone operations, China’s actions should be

referred to as illegal, coercive, aggressive and deceptive (ICAD) operations.37 One U.S. official

has characterized China’s actions as amounting to a “boiling frog” strategy.38

An April 10, 2021, press report states,

China is trying to wear down its neighbors with relentless pressure tactics designed to push

its territorial claims, employing military aircraft, militia boats and sand dredgers to

dominate access to disputed areas, U.S. government officials and regional experts say.

The confrontations fall short of outright military action without shots being fired, but

Beijing’s aggressive moves are gradually altering the status quo, laying the foundation for

China to potentially exert control over contested territory across vast stretches of the Pacific

Ocean, the officials and experts say….

The Chinese are “trying to grind them down,” said a senior U.S. Defense official….

“Beijing never really presents you with a clear deadline with a reason to use force. You

just find yourselves worn down and slowly pushed back,” [Gregory Poling of the Center

for Strategic and International Studies] said.39

31 See, for example, Patrick Mendis and Joey Wang, “China’s Art of Strategic Incrementalism in the South China Sea,”

National Interest, August 8, 2020.

32 See, for example, Alan Dupont, “China’s Maritime Power Trip,” The Australian, May 24, 2014.

33 Jackson Diehl, “China’s ‘Creeping Invasion,” Washington Post, September 14, 2014.

34 See Ian Ralby, “China’s Maritime Strategy: To Own the Oceans by Adverse Possession,” The Hill, March 28, 2023.

35 See, for example, Anders Corr, “China’s Take-And-Talk Strategy In The South China Sea,” Forbes, March 29, 2017.

See also Namrata Goswami, “Can China Be Taken Seriously on its ‘Word’ to Negotiate Disputed Territory?” The

Diplomat, August 18, 2017.

36 See, for example, Masaaki Yatsuzuka, “How China’s Maritime Militia Takes Advantage of the Grey Zone,”

Strategist, January 16, 2023. See also Anika Arora Seth, “Weapons of Choice in China’s Territorial Disputes? Axes,

Knives, ‘Jostling,’” Washington Post, June 22, 2024.

37 See, for example, David Dizon, “ICAD Tactics: ‘Chinese Plane Dropped 8 Flares on PAF Aircraft’s Flight Path,’”

ABS-CBN News, August 12, 2024; Karishma Vaswani, “It Is Time to Give China’s Muscle-Flexing a New Name,”

Taipei Times, July 31, 2024 (also published as Karishma Vaswani, “There’s Nothing Gray About China’s Maritime

Muscle-Flexing; Illegal, Coercive, Aggressive and Deceptive—Why the ICAD Moniker for Beijing’s Actions in the

South China Sea Needs to Be Adopted,” Bloomberg, July 24, 2024); Adam Lockyer, Yves-Heng Lim, and Courtney J.

Fung, “Moving Beyond the Grey Zone: The Case for ICAD,” Interpreter, July 17, 2024; Bill Gertz, “China’s GrayZone Operations ‘Illegal, Coercive, Aggressive, Deceptive,’ Paparo Says,” Washington Times, May 6, 2024; Ken

Moriyasu, “China’s Territorial Claims Illegal, Deceptive: U.S. Indo-Pacific Chief,” Nikkei Asia, May 4, 2024. See also

James Holmes, “Is China at War in the South China Sea?” National Interest, June 29, 2024.

38 Matthew Loh, “China Is Gradually Amping up Its Military Aggression in a ‘Boiling Frog’ Strategy, US Indo-Pacific

Commander Says,” Business Insider, April 28, 2024; Demetri Sevastopulo, “US Pacific Commander Says China Is

Pursuing ‘Boiling Frog’ Strategy,” Financial Times, April 28, 2024.

39 Dan De Luce, “China Tries to Wear Down Its Neighbors with Pressure Tactics,” NBC News, April 10, 2021.

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Use of Coast Guard Ships and Maritime Militia

China asserts and defends its maritime claims primarily with its maritime militia and its coast

guard rather than its navy, although the navy can serve as an “over-the-horizon” backup force

when needed. Operations by the maritime militia are particularly prominent in the SCS. For more

on China’s coast guard and maritime militia, see Appendix E.

Preference for Treating Territorial Disputes on Bilateral Basis

As mentioned above, China appears to prefer discussing maritime territorial disputes with other

countries in the region though bilateral (as opposed to multilateral) engagements. As the largest

country in the region, China may believe that it can more easily gain the upper hand in bilateral

rather than multilateral discussions, particularly since multilateral discussions can provide

settings for other countries in the region to act collectively to oppose China’s actions in the SCS

and ECS. China generally has resisted multilateral approaches to resolving maritime territorial

disputes, stating that such approaches would internationalize the disputes, although the disputes

are by definition international even when addressed on a bilateral basis. A preference for

discussing maritime territorial disputes with other countries in the region on a bilateral basis can

be consistent with a so-called divide-and-conquer strategy for engaging with other countries in

the SCS region.40 China’s participation with the ASEAN states in the 2002 Declaration of

Conduct (DOC) and in negotiations with the ASEAN states on the follow-on binding code of

conduct (COC) (see Appendix C) represents a departure from this general preference, though it

might also be argued that the drawn-out negotiations on the COC are consistent with a “talk and

take” strategy.

Depiction of United States as Outsider Seeking to “Stir Up Trouble”

China resists and objects to the involvement of outside actors, such as the United States, in

maritime disputes in the SCS and ECS, and discourages other countries in the region from

working collectively with outside actors such as the United States to oppose China’s actions in

the SCS and ECS. Statements in China’s state-controlled media sometimes depict the United

States as an outsider or interloper whose actions (including freedom of navigation operations) are

meddling or seeking to “stir up trouble” (or words to that effect) in an otherwise purportedly

peaceful regional situation. Potential or actual Japanese involvement in the SCS is sometimes

depicted in China’s state-controlled media in similar terms. Depicting the United States in this

manner can be viewed as consistent with goals of attempting to drive a wedge between the United

States and its allies and partners in the region and of ensuring maximum leverage in bilateral

(rather than multilateral) discussions with other countries in the region over maritime territorial

disputes.

Island Building and Base Construction

Perhaps more than any other set of actions, China’s island-building (aka land-reclamation) and

base-construction activities at sites that it occupies in the Paracel Islands and Spratly Islands in

the SCS have heightened concerns among U.S. observers that China is rapidly gaining effective

control of the SCS. China’s large-scale island-building and base-construction activities in the SCS

appear to have begun around December 2013, and were publicly reported starting in May 2014.

Awareness of, and concern about, the activities appears to have increased substantially following

40 See, for example, Shi Jiangtao, “Beijing Uses ‘Divide and Conquer’ Tactic with Asean as South China Sea Tensions

Heat Up,” South China Morning Post, September 26, 2024.

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the posting of a February 2015 article showing a series of “before and after” satellite photographs

of islands and reefs being changed by the work.41

China occupies seven sites in the Spratly Islands. It has engaged in island-building and facilitiesconstruction activities at most or all of these sites, and particularly at three of them—Fiery Cross

Reef, Subi Reef, and Mischief Reef, all of which now feature lengthy airfields for supporting

operations by large or high-performance aircraft, as well as substantial numbers of buildings and

other structures. An October 25, 2024, press report states

The Chinese military is constructing a new counter-stealth radar system on a disputed reef

in the South China Sea that would significantly expand its surveillance capabilities in the

region, satellite imagery suggests.

Analysis by Chatham House suggests China is upgrading its outpost on Triton Island, on

the south-west corner of the Paracel archipelago, building what may be a launching point

for an anti-ship missile battery, as well as the sophisticated radar system. 42

Figure 1 and Figure 2 show reported military facilities at sites that China occupies in the SCS,

and reported aircraft, missile, and radar “range rings” extending from those sites. Although other

countries, such as Vietnam, have engaged in their own island-building and facilities-construction

activities at sites that they occupy in the SCS, these efforts are dwarfed in size by China’s islandbuilding and base-construction activities in the SCS.43

Other Actions That Have Heightened Concerns

Additional PRC actions in the SCS and ECS over the last 15 years that have heightened concerns

among U.S. observers include the following, among others:

•

•

•

•

China’s actions in 2012, following a confrontation between PRC and Philippine

ships at Scarborough Shoal in the SCS, to gain de facto control over access to the

shoal and its surrounding fishing areas;

China’s announcement on November 23, 2013, of an air defense identification

zone (ADIZ) over the ECS that includes airspace over the Senkaku Islands;44

frequent patrols by PRC Coast Guard ships—some observers refer to them as

harassment operations—at the Senkaku Islands;

PRC pressure against the small Philippine military presence at Second Thomas

Shoal in the Spratly Islands, where a handful of Philippine military personnel

occupy a beached (and now derelict) Philippine navy amphibious ship;45

41 Mira Rapp-Hooper, “Before and After: The South China Sea Transformed,” Asia Maritime Transparency Initiative

(AMTI) (Center for Strategic and International Studies [CSIS]), February 18, 2015.

42

Rebecca Ratcliffe, “China Building ‘Counter-Stealth’ Radar on Disputed South China Sea Reef, Satellite Pictures

Suggest,” Guardian, October 25, 2024. See also Colin Clark, “China Tightens ‘Counter-Stealth’ Military Radar Net

around South China Sea, Says Report,” Breaking Defense, October 23, 2024; John Pollock and Damien Symon, “How

Beijing Is Closing Surveillance Gaps in the South China Sea,” Chatham House, October 17, 2024.

43 See, for example, “Vietnam’s Island Building: Double-Standard or Drop in the Bucket?,” Asia Maritime

Transparency Initiative (AMTI) (Center for Strategic and International Studies [CSIS]), May 11, 2016. For additional

details on China’s island-building and base-construction activities in the SCS, see, in addition to Appendix E, CRS

Report R44072, Chinese Land Reclamation in the South China Sea: Implications and Policy Options, by Ben Dolven et

al.

44 See CRS Report R43894, China's Air Defense Identification Zone (ADIZ), by Ian E. Rinehart and Bart Elias.

45 See, for example, “Shifting Tactics at Second Thomas Shoal,” Asia Maritime Transparency Initiative (AMTI)

(Center for Strategic and International Studies [CSIS]), August 22, 2024; “Tracking Tensions At Second Thomas

(continued...)

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•

•

a growing civilian PRC presence on some of the sites in the SCS occupied by

China in the SCS, including both PRC vacationers and (in the Paracels)

permanent settlements; and

a new PRC maritime law that went into effect in September 2021 that seeks to

impose new notification and other requirements on foreign ships entering what

China describes as “sea areas under the jurisdiction” of China, prompting some

observers state that the law could lead to increased tensions in the SCS,

particularly if China takes actions to enforce its provisions.46

Apparent Narrow Definition of “Freedom of Navigation”

China regularly states that it supports freedom of navigation and has not interfered with freedom

of navigation, and in November 2023 signed a joint communique along with 18 other AsiaPacific countries recognizing freedom of navigation under the United Nations Convention on the

Law of the Sea (UNCLOS).47 China, however, appears to hold a narrow definition of freedom of

navigation that is centered on the ability of commercial cargo ships to pass through international

waters. In contrast to the broader U.S./Western definition of freedom of navigation (aka freedom

of the seas), the PRC definition does not appear to include operations conducted by military ships

and aircraft. It can also be noted that China has frequently interfered with commercial fishing

operations by non-PRC fishing vessels—something that some observers regard as a form of

interfering with freedom of navigation for commercial ships.

Position Regarding Regulation of Military Forces in EEZs

As mentioned earlier, the position of China and some other countries (i.e., a minority group

among the world’s nations) is that UNCLOS gives coastal states the right to regulate not only

economic activities, but also foreign military activities, in their EEZs.

Shoal,” Asia Maritime Transparency Initiative (AMTI) (Center for Strategic and International Studies [CSIS]), January

30, 2024.

46 See, for example, Raul (Pete) Pedrozo, “China’s Revised Maritime Traffic Safety Law,” International Law Studies

(U.S. Naval War College), Vol. 97, 2021: 956-968; Nguyen Thanh Trung and Le Ngoc Khanh Ngan, “Codifying

Waters and Reshaping Orders: China’s Strategy for Dominating the South China Sea,” Asia Maritime Transparency

Initiative (AMTI) (Center for Strategic and International Studies [CSIS]), September 27, 2021; Navmi Krishna,

“Explained: Why China’s New Maritime Law May Spike Tensions in South China Sea,” Indian Express, September 7,

2021; Brad Lendon and Steve George, “The Long Arm of China’s New Maritime Law Risks Causing Conflict with US

and Japan,” CNN, September 3, 2021; John Feng, “U.S. Says China Maritime Law Poses ‘Serious Threat’ to Freedom

of the Seas,” Newsweek, September 2, 2021; Richard Javad Heydarian, “China’s Foreign Ship Law Stokes South China

Sea Tensions,” Asia Times, September 2, 2021; Alex Wilson, “Beijing’s New Law for Foreign Vessels Won’t Impact

US Navy in South China Sea, Pentagon Says,” Stars and Stripes, September 2, 2021. See also James Holmes, “Are

China And Russia Trying To Attack The Law Of The Sea?” 19FortyFive, August 31, 2021. Regarding a follow-on

regulation relating to this law that went into force in June 2024, see Arran Hope, “New China Coast Guard Regulation

Buttresses PRC Aggression in the South China Sea,” China Brief, June 21, 2024; U.S. Indo-Pacific Command,

“TOPIC: China Coast Guard Regulation No. 3,” USINDOPACOM J06/SJA Tacaid Series, updated May 30, 2024, 6

pp.

47 Marc Jayson Cayabyab, “AsPac Signs Communique on Freedom of Navigation,” Philippine Star, November 26,

2023, which states that the communique was signed at the annual meeting of Asia Pacific Parliamentary Forum

(APPF), and that the other countries were the Philippines, Australia, Brunei, Cambodia, Canada, Chile, Indonesia,

Japan, South Korea, Laos, Malaysia, Mexico, Federated States of Micronesia, Papua New Guinea, Peru, Russia,

Thailand, and Vietnam.

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Figure 1. Reported Military Facilities at SCS Sites Occupied by China

Source: Illustration accompanying Karen Leigh, Peter Martin and Adrian Leung, “Troubled Waters: Where the

U.S. and China Could Clash in the South China Sea,” Bloomberg, December 17, 2020.

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Figure 2. Reported PRC Aircraft, Missile, and Radar Ranges

From PRC-occupied sites in SCS

Source: Asia Maritime Transparency Initiative (AMTI) (Center for Strategic and International Studies [CSIS]),

“Chinese Power Projection Capabilities in the South China Sea,” at https://amti.csis.org/chinese-powerprojection/. The information box on the right side of the figure is part of the graphic as presented at the AMTI

website.

Additional Elements

For additional information on China’s approach to the SCS and ECS, including elements

discussed briefly above as well as the so-called map of the nine-dash line that China uses to

depict its claims in the SCS, see Appendix E.

Assessments of China’s Strengthened Position in SCS

Some observers assess that China’s actions in the SCS have achieved for China a more dominant

or more commanding position in the SCS. For example, U.S. Navy Admiral Philip Davidson, in

responses to advance policy questions from the Senate Armed Services Committee for an April

17, 2018, hearing before the committee to consider nominations, including Davidson’s

nomination to become Commander, U.S. Pacific Command (PACOM),48 stated that “China is

now capable of controlling the South China Sea in all scenarios short of war with the United

States.”49 For additional assessments of China’s strengthened position in the SCS, see Appendix

F.

48 The name of the command has since been changed to the U.S. Indo-Pacific Command (INDOPACOM).

49 Advance Policy Questions for Admiral Philip Davidson, USN Expected Nominee for Commander, U.S. Pacific

Command, p. 18. See also pp. 8, 16, 17, 19, and 43. See also Hannah Beech, “China’s Sea Control Is a Done Deal,

‘Short of War With the U.S.,’” New York Times, September 20, 2018.

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U.S. Position Regarding Issues Relating to SCS and ECS

Overview

The U.S. position regarding issues relating to the SCS and ECS includes the following elements,

among others:

•

•

Freedom of the seas:

• The United States supports the principle of freedom of the seas, meaning the

rights, freedoms, and uses of the sea and airspace guaranteed to all nations in

international law. The United States opposes claims that impinge on the

rights, freedoms, and lawful uses of the sea that belong to all nations.

• U.S. forces routinely conduct freedom of navigation (FON) assertions

throughout the world. These operations are designed to be conducted in

accordance with international law and demonstrate that the United States will

fly, sail, and operate wherever international law allows, regardless of the

location of excessive maritime claims and regardless of current events.50

• The United States, like most other countries, believes that coastal states

under UNCLOS have the right to regulate economic activities in their EEZs,

but do not have the right to regulate foreign military activities in their EEZs.

The United States will continue to operate its military ships in the EEZs of

other countries consistent with this position. (For additional information

regarding the U.S. position on the issue of operational rights of military ships

in the EEZs of other countries, see Appendix G.)

• U.S. military surveillance flights in international airspace above another

country’s EEZ are lawful under international law, and the United States plans

to continue conducting these flights.

Maritime territorial disputes:

• China’s maritime claims in the SCS are unfounded, unlawful, and

unreasonable, and are without legal, historic, or geographic merit.51 China’s

claims to offshore resources across most of the SCS are completely unlawful,

as is its campaign of bullying to control them. China has no legal grounds to

unilaterally impose its will on the region, and has offered no coherent legal

basis for its nine-dashed line claim in the SCS since formally announcing it

in 2009.

• The U.S. position on China’s maritime claims in the SCS is aligned with the

July 12, 2016, award of the arbitral tribunal that was constituted under

50 Statements such as this one, including in particular phrases such as “the United States will fly, sail, and operate

wherever international law allows,” have become recurring elements of U.S. statements issued either in connection

with specific FON operations or as general statements of U.S. policy regarding freedom of the seas. See, for example,

7th Fleet Public Affairs, “7th Fleet Destroyer conducts Freedom of Navigation Operation in South China Sea,”

Commander, U.S. 7th Fleet, January 20, 2022, accessed April 30, 2025, at https://www.c7f.navy.mil/Media/News/

Display/Article/2904786/7th-fleet-destroyer-conducts-freedom-of-navigation-operation-in-south-china-sea/.

51 Department of State, A Free and Open Indo-Pacific, Advancing a Shared Vision, November 4, 2019, states on page

23: “PRC maritime claims in the South China Sea, exemplified by the preposterous ‘nine-dash line,’ are unfounded,

unlawful, and unreasonable. These claims, which are without legal, historic, or geographic merit, impose real costs on

other countries. Through repeated provocative actions to assert the nine-dash line, Beijing is inhibiting ASEAN

members from accessing over $2.5 trillion in recoverable energy reserves, while contributing to instability and the risk

of conflict.”

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•

•

•

•

•

UNCLOS (a treaty to which China is a party) in the case that the Philippines

brought against China. The tribunal’s award rejected China’s maritime claims

as having no basis in international law and sided squarely with the

Philippines on almost all claims. As specifically provided in UNCLOS, the

tribunal’s decision is final and legally binding on both parties.

Consistent with the tribunal’s award, China cannot lawfully assert a maritime

claim—including any EEZ claims derived from Scarborough Reef and the

Spratly Islands—vis-a-vis the Philippines in areas that the tribunal found to

be in the Philippines’ EEZ or on its continental shelf. China’s harassment of

Philippine fisheries and offshore energy development within those areas is

unlawful, as are any unilateral actions by China to exploit those resources.

Since China has failed to put forth a lawful, coherent maritime claim in the

SCS, the United States rejects any claim by China to waters beyond a 12nautical mile territorial sea derived from islands it claims in the Spratly

Islands (without prejudice to other states’ sovereignty claims over such

islands).

The United States stands with its Southeast Asian allies and partners in

protecting their sovereign rights to offshore resources, consistent with their

rights and obligations under international law, and rejects any push to impose

a situation of might makes right in the SCS or the wider region. China’s

unilateral efforts to assert illegitimate maritime claims threaten other nations’

access to vital natural resources, undermine the stability of regional energy

markets, and increase the risk of conflict.52 The United States will not accept

attempts to assert unlawful maritime claims at the expense of law-abiding

nations.53

Article IV of the 1951 U.S.-Philippines Mutual Defense Treaty extends to

armed attacks on Philippine armed forces, public vessels, or aircraft—

including those of its Coast Guard—anywhere in the South China Sea.54

The United States takes no position on competing claims to sovereignty over

disputed land features in the ECS and SCS, but the United States does have a

position on how competing claims should be resolved: These disputes, like

international disputes in general, should be resolved peacefully, without

coercion, intimidation, threats, or the use of force, and in a manner consistent

with international law.

Parties should avoid taking provocative or unilateral actions that disrupt the

status quo or jeopardize peace and security. The United States does not

believe that large-scale island-building with the intent to militarize outposts

52 In a November 20, 2019, speech in Hanoi, Secretary of Defense Mark Esper stated, “China’s unilateral efforts to

assert illegitimate maritime claims threaten other nations’ access to vital natural resources, undermine the stability of

regional energy markets, and increase the risk of conflict.” (U.S. Embassy and Consulate in Vietnam, “Secretary of

Defense Mark T. Esper Remarks at Diplomatic Academy of Vietnam,” November 20, 2019, Hanoi, Vietnam.)

53 In a November 20, 2019, speech in Hanoi, Secretary of Defense Mark Esper stated, “We will not accept attempts to

assert unlawful maritime claims at the expense of law-abiding nations.” (U.S. Embassy and Consulate in Vietnam,

“Secretary of Defense Mark T. Esper Remarks at Diplomatic Academy of Vietnam,” November 20, 2019, Hanoi,

Vietnam.)

54 See, for example, Department of State, “U.S. Support for the Philippines in the South China Sea,” press statement

dated August 19, 2024.

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•

•

on disputed land features is consistent with the region’s desire for peace and

stability.

Claims of territorial waters and EEZs should be consistent with customary

international law of the sea and must therefore, among other things, derive

from land features. Claims in the SCS that are not derived from land features

are fundamentally flawed.

The Senkaku Islands are under the administration of Japan. Unilateral

attempts to change the status quo there raise tensions and do nothing under

international law to strengthen territorial claims.

For examples of U.S. statements describing the U.S. position on issues relating to the SCS and

ECS, see Appendix G.

Freedom of Navigation (FON) Program

Under the U.S. Freedom of Navigation (FON) program, U.S. Navy ships and other U.S. military

forces challenge what the United States views as excessive maritime claims made by other

countries, and otherwise carry out assertions of operational rights. The FON program began in

1979,55 involves diplomatic activities as well as operational assertions by U.S. Navy ships and

other military forces, and is global in scope, encompassing activities and operations directed not

only at China, but at numerous other countries around the world, including U.S. allies and partner

states. DOD stated in 2015 that

As part of the Department’s routine presence activities, the U.S. Navy, U.S. Air Force, and

U.S. Coast Guard conduct Freedom of Navigation operations. These operational activities

serve to protect the rights, freedoms, and lawful uses of the sea and airspace guaranteed to

all nations in international law by challenging the full range of excessive maritime claims

asserted by some coastal States in the region. The importance of these operations cannot

be overstated. Numerous countries across the Asia-Pacific region assert excessive maritime

claims that, if left unchallenged, could restrict the freedom of the seas. These excessive

claims include, for example, improperly-drawn straight baselines, improper restrictions on

the right of warships to conduct innocent passage through the territorial seas of other States,

and the freedom to conduct military activities within the EEZs of other States. Added

together, EEZs in the USPACOM region constitute 38 percent of the world’s oceans. If

these excessive maritime claims were left unchallenged, they could restrict the ability of

the United States and other countries to conduct routine military operations or exercises in

more than one-third of the world’s oceans.56

DOD publishes an annual report on the FON program that includes a listing of FON operations

conducted to challenge excessive maritime claims by various countries, including China. DOD’s

report for FY2023 summarizes

excessive maritime claims that DoD challenged during the period of October 1, 2022,

through September 30, 2023, to preserve the rights, freedoms, and uses of the sea and

airspace guaranteed to all nations by international law. In sum, the United States challenged

29 excessive maritime claims of 17 claimants. The report cites in brackets each claimant’s

specific laws, regulations, and other proclamations articulating the excessive maritime

claims. To maintain the operational security of U.S. military forces, DoD Annual FON

55 For a history of the origin of the FON program, see James Kraska, “An Archival History of the Creation and Early

Implementation of the Freedom of Navigation Program,” Chapter 10 (pages 206-237) of Myron H. Nordquist, John

Norton Moore, and Ronán Long, editors, Cooperation and Engagement in the Asia-Pacific Region, Center for Oceans

Law and Policy, Volume: 23, 2020 (publication date: 28 November 28, 2019).

56 Department of Defense, Asia-Pacific Maritime Security Strategy, undated but released August 2015, pp. 23-24.

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Reports include only general geographic information on the location of operational

challenges and do not specify the precise number of challenges to each excessive maritime

claim.57

For additional information on the FON program, see Appendix H.

Taiwan Strait Transits

In addition to conducting FON operations in the Spratly and Paracel islands, U.S. Navy ships

(and also occasionally U.S. Coast Guard cutters or allied navy ships) steam through the Taiwan

Strait to assert navigational rights under international law. The Taiwan Strait appears to have a

minimum width (which occurs toward its northern end) of more than 67 nautical miles; at other

points, its width is greater, and toward its southern end exceeds 120 nautical miles.58 Subtracting

12 nautical miles of territorial seas (i.e., what are commonly referred to as territorial waters) from

either side of the strait leaves a central corridor of international waters running through the strait

with an apparent minimum width of more than 43 nautical miles that is beyond the territorial sea

of any coastal state, where high seas freedoms of navigation and overflight apply in accordance

with international law.59

57 Department of Defense, Department of Defense Report to Congress, Annual Freedom of Navigation Report, Fiscal

Year 2023, generated on March 8, 2024, released on May 8, 2024, PDF page 3 of 6.

58 Source: CRS measurements of the strait’s width using the distance measurement tool of Google Maps

(https://www.google.com/maps). The minimum width of more than 67 nautical miles that was found by CRS

measurement is toward the strait’s northern end; the widths of more than 120 nautical miles are generally toward the

strait’s southern end. The Google Maps distance measurement tool provides measurements in statute miles, which CRS

converted into nautical miles.

59 For example, a statement issued on June 3, 2023, by the U.S. Navy’s 7 th Fleet regarding a Taiwan Strait transit that

was being conducted at that time by a U.S. Navy destroyer and a Canadian navy frigate stated that the transit was being

conducted “through waters where high-seas freedoms of navigation and overflight apply in accordance with

international law. The ships transit through a corridor in the Strait that is beyond the territorial sea of any coastal State.”

(U.S. 7th Fleet Public Affairs, “7th Fleet Destroyer Transits Taiwan Strait,” June 3, 2023.) Two days later, following an

incident during that transit in which a Chinese navy destroyer crossed in front of the U.S. Navy destroyer in an unsafe

manner, a statement issued by the U.S. Indo-Pacific Command (USINDOPACOM) stated

In accordance with international law, [the U.S. Navy destroyer] USS Chung-Hoon (DDG 93) and

[the Canadian navy frigate] HMCS Montreal (FFH 336) conducted a routine south to north Taiwan

Strait transit June 3 through waters where high seas freedoms of navigation and overflight apply.

During the transit, [the] PLA(N) [i.e., Chinese navy] LUYANG III [class destroyer] DDG 132

(PRC LY 132) executed maneuvers in an unsafe manner in the vicinity of Chung-Hoon. The PRC

LY 132 overtook Chung-Hoon on their [i.e., Chung-Hoon’s] port side and crossed their [i.e.,

Chung-Hoon’s] bow at 150 yards. Chung-Hoon maintained course and slowed to 10 kts to avoid a

collision. The PRC LY 132 crossed Chung-Hoon’s bow a second time starboard to port at 2,000

yards and remained off Chung-Hoon’s port bow. The LY 132’s closest point of approach was 150

yards and its actions violated the maritime ‘Rules of the Road’ of safe passage in international

waters.

(U.S. Indo-Pacific Command Public Affairs, “USINDOPACOM Statement on Unsafe Maritime

Interaction,” June 5, 2023.)

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Issues for Congress

U.S. Strategy for Competing Strategically with China in SCS

and ECS

Overview

Whether and how to compete strategically with China in the SCS and ECS is a choice for U.S.

policymakers to make, based on an assessment of U.S. interests and the potential benefits and

costs of engaging in such a competition in the context of overall U.S. policy toward China,60 U.S.

policy toward the Indo-Pacific,61 and U.S. foreign policy in general.

A key issue for Congress is whether the Administration’s strategy for competing strategically with

China in the SCS and ECS is appropriate and correctly resourced, and whether Congress should

approve, reject, or modify the strategy, the level of resources for implementing it, or both.

Decisions that Congress makes on these issues could substantially affect U.S. strategic, political,

and economic interests in the Indo-Pacific region and elsewhere.

Potential Broader Goals

For observers who conclude that the United States should compete strategically with China in the

SCS and ECS, potential broader U.S. goals for such a competition include but are not necessarily

limited to the following, which are not listed in any particular order and are not mutually

exclusive:

•

•

•

•

•

fulfilling U.S. security commitments in the Western Pacific, including treaty

commitments to Japan and the Philippines;

maintaining and enhancing the U.S.-led security architecture in the Western

Pacific, including U.S. security relationships with treaty allies and partner states;

maintaining a regional balance of power favorable to the United States and its

allies and partners;

defending the principle of peaceful resolution of disputes, under which disputes

between countries should be resolved peacefully, without coercion, intimidation,

threats, or the use of force, and in a manner consistent with international law, and

resisting the emergence of an alternative “might-makes-right” approach to

international affairs;

defending the principle of freedom of the seas, meaning the rights, freedoms, and

uses of the sea and airspace guaranteed to all nations in international law,

including the interpretation held by the United States and many other countries

concerning operational freedoms for military forces in EEZs;

60 For more on overall U.S.-China relations, see CRS In Focus IF10119, China Primer: U.S.-China Relations, by Susan

V. Lawrence and Karen M. Sutter, and CRS Report R41108, U.S.-China Relations: An Overview of Policy Issues, by

Susan V. Lawrence.

61 For more on U.S. policy toward the Indo-Pacific, see CRS Insight IN11814, Biden Administration Plans for an IndoPacific Economic Framework, coordinated by Brock R. Williams; CRS In Focus IF11678, The “Quad”: Security

Cooperation Among the United States, Japan, India, and Australia, coordinated by Emma Chanlett-Avery; CRS In

Focus IF11052, The United Kingdom, France and the Indo-Pacific, by Bruce Vaughn, Derek E. Mix, and Paul Belkin.

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•

•

preventing China from becoming a regional hegemon in East Asia, and

potentially as part of that, preventing China from controlling or dominating the

ECS or SCS; and

pursuing these goals as part of a larger U.S. strategy for competing strategically

and managing relations with China.

Potential Specific Goals

For observers who conclude that the United States should compete strategically with China in the

SCS and ECS, potential specific U.S. goals for such a competition include but are not necessarily

limited to the following, which are not listed in any particular order and are not mutually

exclusive:

•

•

dissuading China from

• carrying out additional base-construction activities in the SCS,

• moving additional military personnel, equipment, and supplies to bases at

sites that it occupies in the SCS,

• initiating island-building or base-construction activities at Scarborough Shoal

in the SCS,

• declaring straight baselines around land features it claims in the SCS,62 or

• declaring an air defense identification zone (ADIZ) over the SCS;63 and

encouraging China to

• reduce or end operations by its maritime forces at the Senkaku Islands in the

ECS,

• halt actions intended to put pressure against the small Philippine military

presence at Second Thomas Shoal in the Spratly Islands (or against any other

Philippine-occupied sites in the Spratly Islands);

• adopt the U.S./Western definition regarding freedom of the seas, including

the freedom of U.S. and other non-PRC military vessels to operate freely in

China’s EEZ; and

• accept and abide by the July 2016 tribunal award in the SCS arbitration case

involving the Philippines and China (see Appendix D).

62 For a discussion regarding the possibility of China declaring straight baselines around land features it claims in the

SCS, see “Reading Between the Lines: The Next Spratly Legal Dispute,” Asia Maritime Transparency Initiative

(AMTI) (Center for Strategic and International Studies [CSIS]), March 21, 2019.

63 For more on the possibility of China declaring an ADIZ over the SCS, see, for example, Minnie Chan, “South China

Sea: Beijing ‘Doesn’t Want to Upset Neighbours’ with Air Defence Zone,” South China Morning Post, November 25,

2020; Carl O. Schuster, “[Opinion] The Air Defense Identification Zone—China’s next South China Sea aggression?”

Rappler, July 7, 2020; Aie Balagtas See and Jeoffrey Maitem, “US Watching if Beijing Declares Air Defense Zone in

South China Sea,” BenarNews, June 24, 2020 (also published as BenarNews, “US Watching if Beijing Declares Air

Defense Zone in South China Sea,” Radio Free Asia, June 24, 2020); Roy Mabasa, “US Commander: ADIZ over South

China Sea Will Impact All Nations in Region,” Manila Bulletin, June 24, 2020; Minnie Chan, “Beijing’s Plans for

South China Sea Air Defence Identification Zone Cover Pratas, Paracel and Spratly Islands, PLA Source Says,” South

China Morning Post, May 31, 2020; Ben Werner, “New Air Bases, Baby Cabbage Key to Chinese Long-Term Claims

in South China Sea,” USNI News, June 3, 2020; “China’s Next Move in the South China Sea,” Economist, June 18,

2020.

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U.S. Strategy for Competing in SCS and ECS Given China’s Approach

China’s approach to maritime disputes in the SCS and ECS, and to strengthening its position over

time in the SCS, discussed earlier in this report, raises a possible question as to how likely a U.S.

strategy for competing strategically with China in the SCS and ECS might be to achieve its goals

if that strategy were characterized by being one or more of the following:

•

•

•

•

one-dimensional rather than multidimensional or whole-of-government;

halting or intermittent rather than persistent;

insufficiently resourced; or

reliant on imposed costs that are not commensurate with the importance that

China appears to have assigned to achieving its goals in the region.

Aligning Actions with Goals

In terms of identifying specific actions for a U.S. strategy for competing strategically with China

in the SCS and ECS, a key element would be to have a clear understanding of which actions are

intended to support which U.S. goals, and to maintain an alignment of actions with policy goals.

For example, U.S. FON operations (FONOPs), which often feature prominently in discussions of

actual or potential U.S. actions, can directly support a general goal of defending the principle of

freedom of the seas, but might support other goals only indirectly, marginally, or not at all.64 A

summary of U.S. actions and how they align with U.S. goals might produce a U.S. version of the

summary of China’s apparent goals and supporting actions shown in Table 1.

Cost-Imposing Actions

Cost-imposing actions are actions intended to impose political/reputational, institutional,

economic, or other costs on China for conducting certain activities in the ECS and SCS, with the

aim of persuading China to stop or reverse those activities. Such cost-imposing actions need not

be limited to the SCS and ECS. As a hypothetical example for purposes of illustrating the point,

one potential cost-imposing action might be for the United States to respond to unwanted PRC

activities in the ECS or SCS by moving to suspend China’s observer status on the Arctic

Council.65 In a May 6, 2019, speech in Finland, then-Secretary of State Michael Pompeo stated

(emphasis added)

64 For discussions bearing on this issue, see, for example, Caitlin Doornbos, “Freedom-of-Navigation Ops Will Not

Dent Beijing’s South China Sea Claims, Experts Say,” Stars and Stripes, April 4, 2019; James Holmes, “Are Freedom

of Navigation Operations in East Asia Enough?” National Interest, February 23, 2019; Zack Cooper and Gregory

Poling, “America’s Freedom of Navigation Operations Are Lost at Sea, Far Wider Measures Are Needed to Challenge

Beijing’s Maritime Aggression,” Foreign Policy, January 8, 2019. See also John Grady, “U.S. Indo-Pacific Diplomacy

Efforts Hinge On FONOPS, Humanitarian Missions,” USNI News, December 4, 2019.

65 For more on the Arctic Council in general, see CRS Report R41153, Changes in the Arctic: Background and Issues

for Congress, coordinated by Ronald O'Rourke. Paragraph 37 of the Arctic Council’s rules of procedure states the

following:

Once observer status has been granted, Observers shall be invited to the meetings and other

activities of the Arctic Council unless SAOs [Senior Arctic Officials] decide otherwise. Observer

status shall continue for such time as consensus exists among Ministers. Any Observer that engages

in activities which are at odds with the Council’s [Ottawa] Declaration [of September 19, 1996,

establishing the Council] or these Rules of Procedure shall have its status as an Observer

suspended.

Paragraph 5 of Annex II of the Arctic Council’s rules of procedure—an annex regarding the accreditation and review of

(continued...)

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The United States is a believer in free markets. We know from experience that free and fair

competition, open, by the rule of law, produces the best outcomes.

But all the parties in the marketplace have to play by those same rules. Those who violate

those rules should lose their rights to participate in that marketplace. Respect and

transparency are the price of admission.

And let’s talk about China for a moment. China has observer status in the Arctic

Council, but that status is contingent upon its respect for the sovereign rights of Arctic

states. The U.S. wants China to meet that condition and contribute responsibly in the

region. But China’s words and actions raise doubts about its intentions. 66

Expanding the potential scope of cost-imposing actions to regions beyond the Western Pacific

might make it possible to employ elements of U.S. power that cannot be fully exercised if the

examination of potential cost-imposing strategies is confined to the Western Pacific. It might also,

however, expand, geographically or otherwise, areas of tension or dispute between the United

States and China.

Actions to impose costs on China can also impose costs, or lead to China imposing costs, on the

United States and its allies and partners. Whether to implement cost-imposing actions thus

involves weighing the potential benefits and costs to the United States and its allies and partners

of implementing those actions, as well as the potential consequences to the United States and its

allies and partners of not implementing those actions.

observers—states the following:

Every four years, from the date of being granted Observer status, Observers should state

affirmatively their continued interest in Observer status. Not later than 120 days before a

Ministerial meeting where Observers will be reviewed, the Chairmanship shall circulate to the

Arctic States and Permanent Participants a list of all accredited Observers and up-to-date

information on their activities relevant to the work of the Arctic Council.

(Arctic Council, Arctic Council Rules of Procedure, p. 9. The document was accessed April 30,

2025, at https://oaarchive.arctic-council.org/items/f06e5457-1246-44d3-a8c1-00016dd585db.

Paragraph 4.3 of the Arctic Council’s observer manual for subsidiary bodies states in part

Observer status continues for such time as consensus exists among Ministers. Any Observer that

engages in activities which are at odds with the Ottawa Declaration or with the Rules of Procedure

will have its status as an Observer suspended.

(Arctic Council. Observer Manual for Subsidiary Bodies, p. 5. The document was accessed April

30, 2025, at https://oaarchive.arctic-council.org/items/ead1bb3b-8189-4cab-8eee-a78e01d21789.)

See also Alyson JK Bailes, “Understanding The Arctic Council: A ‘Sub-Regional’ Perspective,” Journal of Military

and Strategic Studies, Vol. 15, Issue 2, 2013: 48, accessed April 30, 2025, at https://ciaotest.cc.columbia.edu/journals/

jomass/v15i2/f_0030237_24448.pdf; Brianna Wodiske, “Preventing the Melting of the Arctic Council: China as a

Permanent Observer and What It Means for the Council and the Environment,” Loyola of Los Angeles International

and Comparative Law Review, Vol. 315, Issue 2, 2014 (November 1, 2014): 320, accessed April 30, 2025, at

https://digitalcommons.lmu.edu/ilr/vol36/iss2/5/; Sebastian Knecht, “New Observers Queuing Up: Why the Arctic

Council Should Expand—And Expel,” Arctic Institute, April 20, 2015; Evan Bloom, “Establishment of the Arctic

Council,” undated, accessed April 30, 2025, at https://2009-2017.state.gov/e/oes/ocns/opa/arc/ac/

establishmentarcticcouncil/index.htm, which states, “The following paper was authored by Evan Bloom in July 1999

when serving as an attorney in the Office of the Legal Adviser at the U.S. Department of State. Mr. Bloom is now the

Director of the Office of Oceans and Polar Affairs for the Bureau of Oceans and International Environmental and

Scientific Affairs at the U.S. Department of State”; Kevin McGwin, “After 20 years, the Arctic Council Reconsiders

the Role of Observers,” Arctic Today, October 24, 2018.

66 State Department, “Looking North: Sharpening America’s Arctic Focus, Remarks, Michael R. Pompeo, Secretary of

State, Rovaniemi, Finland, May 6, 2019,” accessed April 30, 2025, at https://2017-2021.state.gov/looking-northsharpening-americas-arctic-focus/index.html.

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Contributions from Allies and Partners

Another factor that policymakers may consider are the contributions to a combined U.S.-alliedpartner state strategy for competing strategically with China in the SCS and ECS that are made by

allies such as Japan, the Philippines, Australia, the UK, France, and Germany, as well as potential

or emerging partner countries such as Vietnam, Indonesia, and India. Most or all of the countries

just mentioned have taken steps of one kind or another in response to China’s actions in the SCS

and ECS.67

Until the later months of 2021, a particular question had concerned the kinds of actions that thenPhilippine president Rodrigo Duterte might be willing to take, given what had been, until the later

months of 2021, his frequently nonconfrontational policy toward China regarding the SCS. Since

the later months of 2021, and particularly since Ferdinand Marcos Jr. assumed the office of

president of the Philippines on June 30, 2022, Philippine actions, while continuing to show an

interest in seeking cooperative arrangements with China where possible,68 have also reflected a

greater willingness to confront China regarding the SCS and to work with the United States and

other countries in doing so.69

67 See, for example, Nikkei staff writers, “Japan to Grant Radar to Philippines amid South China Sea Tensions,” Nikkei

Asia, December 1, 2024; Zach Hope, “In the Job Seven Days, Asia’s Newest Leader Is Already Standing Up to China,”

Sydney Morning Herald, October 28, 2024; Joe Keary, “Military Challenges to China’s South China Sea Claims Are

Increasing,” Strategist, October 22, 2024; Rahman Yaacob, “Commentary: Latest Natuna Islands Incident Hints at

Change in Indonesia’s Approach to China,” Channel News Asia (CNA), October 27, 2024; Richard Heydarian, “How

South China Sea Disputes Are Uniting Asean States,” South China, Morning Post, October 14, 2024; Michael Delizo,

“Philippines, Vietnam Set to Sign Defense Cooperation Agreement,” ABS-CBN News, August 28, 2024; Akira Kitado,

“Japan Boosts Defenses on Remote Islands Near Taiwan amid China Fears,” Nikkei Asia, March 31, 2024; Julian

Ryall, “Japan to Help Improve Maritime Capabilities of 4 Asean States amid South China Sea Row,” South China

Morning Post, February 13, 2024; Richard Javad Heydarian, “Indonesia, Philippines Draw Together vis-a-vis China,”

Asia Times, January 12, 2024.

68 See, for example, Adinda Khaerani Epstein, “The Philippines Reshapes Its Policies on the U.S. and China,”

Geopolitical Intelligence Services (GIS), February 28, 2025; Joseph Pedrajas, “Philippines Remains Optimistic about

Positive Relations with China,” Manila Bulletin, September 26, 2024; Ramon Royandoyan, “Marcos Says South China

Sea Claim Isn’t ‘Imaginary,’ Urges Diplomacy,” Nikkei Asia, July 22, 2024; Ramon Royandoyan and Yuki Fujita,

“Philippines to Seek Diplomatic Solutions in South China Sea,” Nikkei Asia, July 8, 2024; Mikhail Flores and Karen

Lema, “Philippines President Orders De-Escalation in South China Sea, Military Chief Says,” Reuters, July 4, 2024;

Jacob Lazaro and Nestor Corrales, “PH, China Ministers Talk De-Escalation—But ‘Monster’ Back in EEZ,” Philippine

Daily Inquirer, July 4, 2024 (referring to a very large China Coast Guard cutter sometimes called the Monster);

Sebastian Strangio, “Philippines Says it Wants ‘Dialogue’ With China Following Maritime Clash,” Diplomat, June 26,

2024; Neil Jerome Morales, “Philippines Says It Wants to Work with China to Manage Tensions in South China Sea,”

Reuters, June 25, 2024; Jim Gomez, “Philippines Says It Won’t Back Down, But Won’t Start a War, after Clash with

Chinese Coast Guard,” Associated Press, June 23, 2024.

69 See, for example, Micah McCartney, “US Ally ‘Actively Challenging’ China in Contested Waters,” Newsweek,

January 29, 2025; Jeoffrey Maitem, “Philippines Launches ‘Surface Action Groups’ to Strengthen South China Sea

Patrols and Defence,” South China Morning Post, January 24, 2025; Haroro J. Ingram, “Archipelago of Resistance:

The Philippines Is Rising to Meet the China Threat, But It Has a Crucial Year Ahead,” War on the Rocks, December

11, 2025; Harrison Prétat and Gregory B. Poling, “Manila and Beijing Clarify Select South China Sea Claims,” Center

for Strategic and International Studies (CSIS), November 21, 2024; Rebecca Tan, “Philippines Pivots from Battling

Militants to Projecting Power at Sea,” Washington Post, November 16, 2024; Karen Lema, Mikhail Flores, and Joe

Cash, with additional reporting by Costas Pitas, “China Summons Philippine Ambassador over New Maritime Laws,”

Reuters, November 8, 2024; Ramon Royandoyan and Yukio Tajima, “Philippines’ Marcos Signs Laws to Assert South

China Sea Rights,” Nikkei Asia, November 8 2024; Jeoffrey Maitem, “Philippines Strengthens South China Sea

Strategy with US$56 Million Thitu Island Upgrade,” South China Morning Post, October 27 (updated October 28),

2024; Joshua Kurlantzick and Abi McGowan, “Why Tensions in the South China Sea Are Bolstering the U.S.Philippines Alliance,” Council on Foreign Relations, September 5, 2024; Mikhail Flores and Karen Lema, “Philippines

Says Pact with Japan Takes Defence Ties to Unprecedented High,” Reuters, July 8, 2024; Don McLain Gill, “Marcos’s

Annual Address Shows Steely Resolve On Maritime Rights,” Nikkei Asia, July 29, 2024; Dylan Butts, “Philippines to

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Certain U.S. actions appear intended in part to encourage U.S. allies and partners in Southeast

Asia to take stronger steps to challenge or oppose China on matters relating to the SCS.70 U.S.

actions to provide maritime-related security assistance to countries in the region have been

carried out in part under the Indo-Pacific Maritime Security Initiative (IP MSI), an initiative

(previously named the Southeast Asian MSI) that was originally announced by the Obama

Administration in May 201571 and subsequently legislated by Congress72 to provide, initially,

$425 million in maritime security assistance to those four countries over a five-year period. In

addition to strengthening security cooperation with U.S. allies in the region, the United States has

taken actions to increase U.S. defense and intelligence cooperation with Vietnam and Indonesia.73

Some observers have argued that there may be limits to how far U.S. allies and partners in the

region might be willing to go to challenge or oppose China on matters relating to the SCS,

particularly if doing so could antagonize China or create a risk of becoming involved in a U.S.-

‘Respond Appropriately’ to Chinese ‘Harassment’ in South China Sea, Military Chief Says,” CNBC, July 5, 2024; Jim

Gomez, “Philippine Military Chief Warns His Forces Will Fight Back If Assaulted Again in Disputed Sea,” Associated

Press, July 4, 2024.

70 See, for example, Poppy McPherson, Karen Lema, and Devjyot Ghoshal, “How the U.S. Courted the Philippines to

Thwart China,” Reuters, November 29, 2024; Hau Dinh and Yves Dam Van, “US to ASEAN: Reconsider Deals with

Blacklisted China Firms,” Associated Press, September 10, 2020; Lynn Kuok, “Southeast Asia Stands to Gain as US

Hardens South China Sea Stance,” Nikkei Asian Review, August 17, 2020; Bhavan Jaipragas, “US Shift on South China

Sea May Help Asean’s Quiet ‘Lawfare’ Resolve Dispute,” South China Morning Post, July 17, 2020.

In a September 26, 2023, speech at Harvard, Secretary of the Navy Carlos Del Toro stated

In 2020, when China embarked on a concerted effort to intimidate Malaysia out of its rightful

offshore resources, the U.S. Seventh Fleet’s Task Force 76 began a remarkable prototype operation,

pioneering a new approach to support our partners’ civilian vessels in standing up to China’s

coercive maritime insurgency in the South China Sea.

U.S. Navy and Marine Corps units from several ship classes took part—including a littoral combat

ship, a destroyer, a cruiser, and the large-deck amphibious assault ship USS America (LHA 6) with

its full complement of Marines.

Joining forces with a frigate from the Royal Australian Navy, Task Force 76 established and

maintained a persistent presence in determined support of a partner’s sovereign, internationallyrecognized rights. China backed down.

(U.S. Navy, “SECNAV Delivers Remarks at Harvard Kennedy School,” speech by Carlos Del

Toro, September 26, 2023.)

71 Secretary of Defense Speech, IISS Shangri-La Dialogue: “A Regional Security Architecture Where Everyone Rises,”

As Delivered by Secretary of Defense Ash Carter, Singapore, Saturday, May 30, 2015, accessed April 30, 2025, at

https://www.defense.gov/News/Speeches/Speech/Article/606676/iiss-shangri-la-dialogue-a-regional-securityarchitecture-where-everyone-rises/. See also Prashanth Parameswaran, “America’s New Maritime Security Initiative

for Southeast Asia,” The Diplomat, April 2, 2016; Prashanth Parameswaran, “US Launches New Maritime Security

Initiative at Shangri-La Dialogue 2015,” The Diplomat, June 2, 2015; Aaron Mehta, “Carter Announces $425M In

Pacific Partnership Funding,” Defense News, May 30, 2015. See also Megan Eckstein, “The Philippines at Forefront of

New Pentagon Maritime Security Initiative,” USNI News, April 18, 2016 (updated April 17, 2016).

72 Section 1263 of the National Defense Authorization Act for Fiscal Year 2016 (S. 1356/P.L. 114-92 of November 25,

2015; 10 U.S.C. 2282 note), as amended by Section 1289 of the National Defense Authorization Act for Fiscal Year

2017 (S. 2943/P.L. 114-328 of December 23, 2016).

73 See, for example, White House, “Joint Leaders’ Statement: Elevating United States-Vietnam Relations to a

Comprehensive Strategic Partnership,” September 11, 2023; Peter Baker and Katie Rogers, “Biden Forges Deeper Ties

With Vietnam as China’s Ambition Mounts,” New York Times, September 10, 2023; Jon Emont, Catherine Lucey, and

Katy Stech Ferek, “Biden Seeks Stronger Vietnam Ties in Bid to Counter China,” Wall Street Journal, September 10,

2023; Matt Viser and Meryl Kornfield, “Biden Visits Vietnam to Bolster Alliance Confronting China,” Washington

Post, September 10, 2023; Sui-Lee Wee, “Vietnam and U.S. Forge Deeper Ties as Worries Rise About China,” New

York Times, September 8, 2023.

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China dispute or confrontation.74 For U.S. policymakers, a key question is how effective the steps

taken by allies and partner countries have been, whether those steps could be strengthened, and

whether they should be undertaken independent of or in coordination with the United States.

U.S. Strategy During First Trump Administration

U.S. strategy for competing strategically with China in the SCS and ECS during the first Trump

Administration included but was not necessarily limited to the following general lines of effort:75

•

•

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•

•

exposing and criticizing China’s actions in the SCS (including so-called namingand-shaming actions),76 and reaffirming the U.S. position on issues relating to the

SCS and ECS, on a recurring basis;

imposing economic sanctions on PRC firms and officials linked to China’s

activities in the SCS;

conducting naval presence and FON operations in the SCS and Taiwan Strait

transits with U.S. Navy ships and (more recently) U.S. Coast Guard cutters;

conducting overflight operations in the SCS and ECS with U.S. Air Force

bombers;

bolstering U.S. military presence and operations in the Indo-Pacific region in

general, and developing new U.S. military concepts of operations for countering

PRC military forces in the Indo-Pacific region.

maintaining and strengthening diplomatic ties and security cooperation with, and

providing maritime-related security assistance to, countries in the SCS region;

and

encouraging allied and partner states to do more individually and in coordination

with one another to defend their interests in the SCS region.

Specific actions taken by the Trump Administration included the following, among others:

•

As an apparent cost-imposing measure, DOD announced on May 23, 2018, that it

was disinviting China from the 2018 RIMPAC (Rim of the Pacific) exercise.77

74 See, for example, Derek Grossman, “Biden Hopes for Vietnam Breakthrough, Washington and Hanoi Have Been

Inching Closer, But It’s a Complicated Dance,” Foreign Policy, May 9, 2023.

75 For additional discussion of the Trump Administration’s strategy for competing strategically with China in the SCS

and ECS, see, for example, Felix K. Chang, “From Pivot to Defiance: American Policy Shift in the South China Sea,”

Foreign Policy Research Institute, August 24, 2020; Michael McDevitt, “Washington Takes a Stand in the South China

Sea,” CNA (Arlington, VA), September 8, 2020.

76 See, for example, Wendy He, and Haridas Ramasamy, “Naming and Shaming China: America’s Strategy of

Rhetorical Coercion in the South China Sea,” Contemporary Southeast Asia, vol. 42, no. 3, 2020: 317–345.

77 RIMPAC is a U.S.-led, multilateral naval exercise in the Pacific involving naval forces from more than two dozen

countries that is held every two years. At DOD’s invitation, China participated in the 2014 and 2016 RIMPAC

exercises. DOD had invited China to participate in the 2018 RIMPAC exercise, and China had accepted that invitation.

DOD’s statement regarding the withdrawal of the invitation was reprinted in Megan Eckstein, “China Disinvited from

Participating in 2018 RIMPAC Exercise,” USNI News, May 23, 2018. See also Gordon Lubold and Jeremy Page, “U.S.

Retracts Invitation to China to Participate in Military Exercise,” Wall Street Journal, May 23, 2018. See also Helene

Cooper, “U.S. Disinvites China From Military Exercise Amid Rising Tensions,” New York Times, May 23, 2018;

Missy Ryan, “Pentagon Disinvites China from Major Naval Exercise over South China Sea Buildup,” Washington

Post, May 23, 2018; James Stavridis, “U.S. Was Right to Give China’s Navy the Boot,” Bloomberg, August 2, 2018.

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•

In November 2018, national security adviser John Bolton said the U.S. would

oppose any agreements between China and other claimants to the South China

Sea that limit free passage to international shipping.78

In January 2019, the then-U.S. Chief of Naval Operations, Admiral John

Richardson, reportedly warned his PRC counterpart that the U.S. Navy would

treat China’s coast guard cutters and maritime militia vessels as combatants and

respond to provocations by them in the same way as it would respond to

provocations by PRC navy ships.79

On March 1, 2019, then-Secretary of State Michael Pompeo stated, “As the

South China Sea is part of the Pacific, any armed attack on Philippine forces,

aircraft, or public vessels in the South China Sea will trigger mutual defense

obligations under Article 4 of our Mutual Defense Treaty [with the

Philippines].”80 (For more on this treaty, see Appendix B.)

On July 13, 2020, then-Secretary Pompeo issued a statement that strengthened,

elaborated, and made more specific certain elements of the U.S. position

regarding China’s actions in the SCS. (For the text of this statement, see

Appendix G.)

On August 26, 2020, then-Secretary Pompeo announced that the United States

had begun “imposing visa restrictions on People’s Republic of China (PRC)

individuals responsible for, or complicit in, either the large-scale reclamation,

construction, or militarization of disputed outposts in the South China Sea, or the

PRC’s use of coercion against Southeast Asian claimants to inhibit their access to

offshore resources.”81

On January 14, 2021, then-Secretary Pompeo announced additional sanctions

against PRC officials, including executives of state-owned enterprises and

officials of the Chinese Communist Party and China’s navy “responsible for, or

complicit in, either the large-scale reclamation, construction, or militarization of

disputed outposts in the South China Sea, or the PRC’s use of coercion against

Southeast Asian claimants to inhibit their access to offshore resources in the

South China Sea.”82

78 Jake Maxwell Watts, “Bolton Warns China Against Limiting Free Passage in South China Sea,” Wall Street Journal,

November 13, 2018.

79 See Demetri Sevastopulo and Kathrin Hille, “US Warns China on Aggressive Acts by Fishing Boats and Coast

Guard; Navy Chief Says Washington Will Use Military Rules of Engagement to Curb Provocative Behavior,” Financial

Times, April 28, 2019. See also Shirley Tay, “US Reportedly Warns China Over Hostile Non-Naval Vessels in South

China Sea,” CNBC, April 29, 2019; Ryan Pickrell, “China’s South China Sea Strategy Takes a Hit as the US Navy

Threatens to Get Tough on Beijing’s Sea Forces,” Business Insider, April 29, 2019; Tyler Durden, “‘Warning Shot

Across The Bow:’ US Warns China On Aggressive Acts By Maritime Militia,” Zero Hedge, April 29, 2019; Ankit

Panda, “The US Navy’s Shifting View of China’s Coast Guard and ‘Maritime Militia,’” Diplomat, April 30, 2019;

Ryan Pickrell, “It Looks Like the US Has Been Quietly Lowering the Threshold for Conflict in the South China Sea,”

Business Insider, June 19, 2019.

80 State Department, Remarks With Philippine Foreign Secretary Teodoro Locsin Jr., Remarks [by] Michael R.

Pompeo, Secretary of State, March 1, 2019, accessed April 30, 2025, at https://2017-2021.state.gov/remarks-withphilippine-foreign-secretary-teodoro-locsin-jr/index.html.

81 Department of State, “U.S. Imposes Restrictions on Certain PRC State-Owned Enterprises and Executives for Malign

Activities in the South China Sea,” press statement, Michael R. Pompeo, Secretary of State, August 26, 2020.

82 Department of State, “Protecting and Preserving a Free and Open South China Sea,” January 14, 2021. See also

Matthew Lee, “US Imposes New Sanction on Beijing over South China Sea,” Associated Press, January 14, 2021.

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•

Also on January 14, 2021, the Commerce Department added China’s state-owned

Chinese National Offshore Oil Corporation (CNOOC) to the Entity List,

restricting exports to that firm, citing CNOOC’s role in “helping China intimidate

neighbors in the South China Sea.”83

U.S. Strategy During Biden Administration

Overview

The Biden Administration continued a number of the general lines of effort listed above in the

section on U.S. strategy during the first Trump Administration. Among other things, the Biden

Administration took steps to expose China’s actions in the SCS,84 reaffirmed the U.S. position on

issues relating to the SCS and ECS, worked to strengthen ties with allies and partners in the

region, and continued U.S. efforts to provide maritime-related security assistance to those

countries.85 The Navy and Air Force continued to operate in the broader waters of the SCS and

the airspace above, and the Navy has continued to conduct FON operations in the SCS and

Taiwan Strait transits, with some observers comparing the frequency of FON operations and

Taiwan Strait transits to their frequency during the Trump Administration. The U.S. Indo-Pacific

Command seeks to counter PRC efforts to engage in so-called lawfare86 regarding the SCS and

ECS.87

Cooperation with the Philippines

Reported developments in 2023 and 2024 regarding U.S. cooperation with the Philippines

included the following:

•

In February 2023, the United States and the Philippines announced an agreement

to expand their Enhanced Defense Cooperation Arrangement (EDCA) to permit

83 Department of Commerce, “Commerce Adds China National Offshore Oil Corporation to the Entity List and

Skyrizon to the Military End-User List,” January 14, 2021. See also Ben Lefebvre, “U.S. Bans Exports to China's

State-Owned Oil Company CNOOC,” Politico Pro, January 14, 2021.

84 Philip Heijmans, “US Spends Big to Highlight Beijing’s Tactics in South China Sea,” Bloomberg, March 6, 2024.

85 See, for example, Pia Lee-Brago, “‘Many Nations’ Ask US Coast Guard for Help,” Philippine Star (Philstar.com),

August 29, 2024; Ian Laqui, “US Taking Twofold Stand vs China's Bullying in South China Sea—Coast Guard

Admiral,” Philippine Star (Philstar.com), August 28, 2024; August 28, 2024; Ryo Nakamura, “U.S. Seeks Military

Access in Philippine Eastern Seaboard,” Nikkei Asia, September 23, 2023; Seth Robson, “US, Vietnam Coast Guard

Cooperation Grows Tighter after Biden Visit,” Stars and Stripes, September 22, 2023; Joe Gould, “U.S. to Announce

Donation of Cargo Aircraft, Cutters to the Philippines,” Politico Pro, May 1, 2023; John Bradford, “U.S. Coast Guard

Is Helping Southeast Asians Protect Their Seas,” Foreign Policy, March 9, 2023.

86 Definitions of lawfare include but are not limited to “the strategic use of legal proceedings to intimidate or hinder an

opponent” (“Lawfare,” Collins Dictionary, accessed May 1, 2025, at

https://www.collinsdictionary.com/us/dictionary/english/lawfare) and “the use of legal systems and institutions to affect

foreign or domestic affairs, as a more peaceful and rational alternative, or as a less benign adjunct, to warfare”

(Lawfare,” Wikipedia, updated April 18, 2025, accessed May 1, 2025, at https://en.wikipedia.org/wiki/Lawfare).

87 See, for example, Bill Gertz, “In the Skies, on the Seas and into the Courts: U.S. Confronts Chinese ‘Lawfare,’”

Washington Times, August 30, 2024. See also “Counter-Lawfare” in USINDOPACOM, “J06 Office of the Staff Judge

Advocate,” undated, accessed May 1, 2025, at https://www.pacom.mil/Contact/Directory/J0/J06-Staff-JudgeAdvocate/#legalvigilancedispatches; Jessica Williams, “Legitimizing and Operationalizing US Lawfare, The

Successful Pursuit of Decisive Legal Combat in the South China Sea,” Journal of Indo-Pacific Affairs, Spring 2021: 17.

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U.S. military access to four additional military facilities in the Philippines.88 In

April 2023, the two governments identified the four additional sites.89

Also in February 2023, the United States and the Philippines agreed to restart

U.S.-Philippine joint patrols in the SCS, which had been suspended in 2016,

during Duterte’s period as president. The Philippines reportedly has also held

talks with Japan and Australia about conducting joint patrols in the SCS with

those countries.90

In March 2023, it was reported that “Japan, the Philippines and the United States

plan to set up a trilateral framework involving their national security advisers”

for “boosting deterrence against China and preparing for a potential crisis over

Taiwan.”91

Also in May 2023, the United States and the Philippines released updated

bilateral defense guidelines92 that, among other things, addressed the

circumstances under which U.S. forces would come to the aid of the Philippines

under the 1951 U.S.-Philippines mutual defense treaty.93

In early June 2023, Philippine coast guard cutters participated in a first-ever

trilateral exercise with U.S. and Japanese coast guard cutters that took place in

SCS waters off Bataan province.94

88 Jim Garamone, “U.S.-Philippine Alliance Strengthens as it Enters New Phase,” DOD News, February 2, 2023.

89 Department of Defense, “Philippines, U.S. Announce Locations of Four New EDCA Sites,” news release, April 3,

2023; Department of Defense, “Readout of U.S.-Philippines 2+2 Ministerial Dialogue,” news release, April 11, 2023;

Rene Acosta, “Philippines Announce 4 New Locations to Host U.S. Troops,” USNI News, April 3, 2023; Jim Gomez,

“Philippines Names 4 New Camps for US Forces amid China Fury,” Associated Press, April 3, 2023; Karen Lema,

“Philippines Reveals Locations of 4 New Strategic Sites for U.S. Military Pact,” Reuters, April 3, 2023.

90 Reuters,“Joint Philippines-U.S. Patrols in South China Sea May Begin by Third Quarter—Envoy,” Reuters, May 8,

2023; Karen Lema, “Japan, Australia May Conduct South China Sea Patrols with U.S., Philippine—Ambassador,”

Reuters, February 28, 2023; Agence France Presse, “US ‘Committed’ To Joint Sea Patrols With Philippines: US Navy

Chief,” Barron’s, February 22, 2023; Karen Lema, “Australia, Philippines Discuss joint South China Sea Patrols,”

Reuters, February 22, 2023; Jim Gomez and Edna Tarigan, “Philippines Eyes South China Sea Patrols with US,

Australia,” Associated Press, February 22, 2023; Karen Lema, “Philippines, U.S. Discuss Joint Coast Guard Patrols in

South China Sea,” Reuters, February 20, 2023.

See also Sebastian Strangio, “Joint South China Sea Patrols Could Begin in 2023, Philippine Official Says,” Diplomat,

August 10, 2023; Jason Gutierrez (Benar News), “Philippines, US to Launch Joint South China Sea Patrols This Year:

Official,” Radio Free Asia, August 9, 2023; Kristine Daguno-Bersamina, “Philippines, US Expected to Start Joint

Patrols in West Philippine Sea by Year-End—NSC,” Philippine Star, August 5, 2023; Yusuke Takeuchi and Yukihiro

Sakaguchi, “U.S., Philippines and Japan eye regular South China Sea exercises,” Nikkei Asia, June 17, 2023.

91 Kyodo News, “Japan, Philippines, U.S. to Set Up 3-Way Security Framework,” Kyodo News, March 28, 2023. See

also Alan Robles, and Raissa Robles, “South China Sea: Philippines, US, Japan to Step Up Maritime Cooperation to

Deter Beijing’s Aggression,” South China Morning Post, April 13, 2024; Mark Magnier, “Biden-Kishida-Marcos Jnr

Meeting Shows ‘Ironclad’ Support for Philippines amid China Confrontations,” South China Morning Post, April 11,

2024; Ken Moriyasu and Ramon Royandoyan, “First U.S.-Japan-Philippines Trilateral to Address China’s ‘Gray Zone’

Tactics,” Nikkei Asia, April 1, 2024; Hal Brands, “Biden Counters China by Partnering Japan and the Philippines,”

Bloomberg, March 27, 2024.

92 The United States and the Republic of the Philippines Bilateral Defense Guidelines, undated, 6 pp., accessed April

30, 2025, at https://media.defense.gov/2023/May/03/2003214357/-1/-1/0/THE-UNITED-STATES-AND-THEREPUBLIC-OF-THE-PHILIPPINES-BILATERAL-DEFENSE-GUIDELINES.PDF.

93 See, for example, Felix K. Chang, “America and the Philippines Update Defense Guidelines,” Foreign Policy

Research Institute (FPRI), May 24, 2023.

94 Yuichi Shiga, “Japan, U.S., Philippines Reinforce Collaboration in Marine Security,” Nikkei Asia, June 2, 2023;

CNN Philippines Staff, “PH, Japan, and US to Hold First Trilateral Joint Coast Guard Drills in June,” CNN, May 29,

2023; Andreo Calonzo, “US, Japan, Philippines to Hold Drills Amid China Tensions,” Bloomberg, May 28 (updated

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In November 2023, the United States and Philippine militaries began joint air and

sea patrols in the SCS.95

In January 2024, it was reported that “an air base in the Philippines is set to

receive a major upgrade to accommodate U.S. aircraft under a plan to strengthen

deterrence against China. Already the site of many U.S.-funded improvements

through the 2014 Enhanced Defense Cooperation Agreement (EDCA) between

the United States and the Philippines, the Philippine Air Force’s Basa Air Base’s

latest project will be a 625,000-square-foot transient parking apron.”96

Also in January 2024, it was reported that “the Philippines and the US plan to

hold what could be their largest military exercises in April, in a show of strength

of their alliance amid heightened tensions in the South China Sea.”97

In November 2024, it was reported that “the Pentagon has revealed the existence

of a forward-deployed task force in the Philippines focused on supporting

Manila’s maritime operations in the South China Sea. Task Force-Ayungin,

composed of American service members and named after the Philippine

designation for Second Thomas Shoal, was seen for the first time on Wednesday

[November 20] during Secretary of Defense Lloyd Austin’s visit to U.S. and

Philippine troops in Palawan.”98

Assessing U.S. Strategy

In assessing whether U.S. strategy for competing strategically with China in the SCS and ECS is

appropriate and correctly resourced, potential questions that Congress may consider include but

are not necessarily limited to the following:

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•

•

•

Has the Administration correctly assessed China’s approach to maritime disputes

in the SCS and ECS, and to strengthening its position over time in the SCS?

Has the Administration correctly identified the U.S. goals to be pursued in

competing strategically with China in the SCS and ECS? If not, how should the

Administration’s list of U.S. goals be modified?

Are the Administration’s actions correctly aligned with its goals? If different

goals should be pursued, what actions should be taken to support them?

Has the Administration correctly incorporated cost-imposing strategies and

potential contributions from allies and partners into its strategy? If not, how

should the strategy be modified?

May 29), 2023; Rene Acosta, “Philippine Coast Guard Will Hold First-Ever Trilateral Exercise with U.S., Japan,”

USNI News, May 23, 2023.

95 Mikhail Flores and Karen Lema, “Philippines Launches Joint Sea, Air Patrols with US Military,” Reuters, November

21, 2023; Kathrin Hille, “US and Philippines Launch Joint Air and Sea Patrols to Counter China,” Financial Times,

November 21, 2023; Aaron-Matthew Lariosa, “U.S., Philippines Begin Three Days of Joint Patrols in the South China

Sea,” USNI News, November 21, 2023.

96 Aaron-Matthew Lariosa, “Philippine Air Base Gets U.S.-Funded Upgrade Under China Deterrence Plan,” USNI

News, January 29, 2024.

97 Ditas B Lopez, “Philippines Eyes Expanded Military Drills With US in April,” Bloomberg, January 30, 2024.

98 Aaron-Matthew Lariosa, “U.S. Supporting Philippine Operations in South China Sea with Forward-Deployed Task

Force,” USNI News, November 21, 2024. See also Karen Lema, “U.S. Backs Philippine Forces in South China Sea

with Task Force,” Reuters, November 21, 2024; Cliff Harvey Venzon, “US Says Its Forces Are Supporting Philippines

in South China Sea,” Bloomberg, November 21, 2024.

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•

Is the Administration requesting an appropriate level of resources for

implementing its strategy? If not, how should the level of resources be modified?

How does the Administration’s strategy for competing strategically in the SCS

and ECS compare with China’s approach to maritime disputes in the SCS and

ECS, and to strengthening its position over time in the SCS?

Appendix I presents a bibliography of some recent writings by observers regarding U.S. strategy

for competing strategically with China in the SCS and ECS.

Risk of Incident, Crisis, or Conflict Involving U.S. Forces

Risk Relating to U.S. and PRC Military Operations In SCS

Some observers—citing both incidents dating back to 2001 between U.S. and PRC ships and

aircraft in China’s near-seas areas (see Appendix A), as well as more recent events—have

expressed concern that stepped-up U.S. and PRC military ship and aircraft operations in the SCS

could increase the risk of a miscalculation or inadvertent action that could cause an accident or

lead to an incident that in turn could escalate into a crisis or conflict.99

Risk Relating to Maritime Territorial Disputes Involving Allies

Some observers are concerned that maritime territorial disputes in the ECS and SCS could lead to

a crisis or conflict between China and a neighboring country such as Japan or the Philippines, and

that the United States could be drawn into such a crisis or conflict as a result of obligations the

United States has under bilateral security treaties with Japan and the Philippines.100 Regarding

this issue, potential oversight questions for Congress include the following:

99 See, for example, James Stavridis, “Near-Collisions at Air and Sea Show China’s New Recklessness, If US Forces

Hadn’t Shown Restraint, Scores of Lives Could Have Been Lost. Wars Have Started for Less,” Bloomberg, June 6,

2023; Sarang Shidore, “Could a US-China War Begin over the Philippines?” Responsible Statecraft, May 15, 2023;

Justin Katz, “Xi Likely ‘Not Aware’ of All Chinese Gray Zone Operations, US Intel Officer Says,” Breaking Defense,

April 5, 2023. See also “America and China Try to Prevent Military Mishaps and Miscalculations,” Economist, June

16, 2022; Risky Competition: Strengthening U.S.-China Crisis Management, International Crisis Group, Asia Report

Number 324, May 20, 2022, 34 pp.

100 See, for example, Chris Panella, “US Ally Says It Expects America to Intervene If China Tries to Take a Rusting

World War II Warship in the South China Sea,” Business Insider, September 16, 2024; Cecilia Vega, Aliza Chasan,

Andy Court, Jacqueline Williams, Annabelle Hanflig, “China Rams Philippine Ship While 60 Minutes on Board; South

China Sea Tensions Could Draw U.S. In,” CBS News, September 15, 2024; Jennifer Jett, “Why the U.S. Could Get

Drawn into a Conflict in the South China Sea,” NBC News, August 18, 2024; Mike Ives, “Why Are There Fears of War

in the South China Sea?” New York Times, August 12, 2024; Craig Singleton, “China and the U.S. Are Careening

Toward a South China Sea Crisis,” Foreign Policy, July 23, 2024; Dylan Butts, “China Is Testing the Limits of a

Critical U.S.-Philippines Defense Pact—Will Washington Respond?” CNBC, June 27 (updated June 30), 2024; Sarang

Shidore, “The South China Sea Risks a Military Crisis,” Foreign Policy, May 31, 2024; Rebecca Tan, Regine Cabato,

and Laris Karklis, “Asia’s Next War Could Be Triggered by a Rusting Warship on a Disputed Reef,” Washington Post,

April 26, 2024; Mallory Shelbourne and Sam LaGrone, “China’s Attacks on Philippine Resupply Missions Test 70Year-Old Defense Pact,” USNI News, March 29, 2024; Dean Cheng, Carla Freeman, Brian Harding, and Andrew

Scobell, “Are China and the Philippines on a Collision Course? China’s Gray Zone Operations Risk a War that Could

Draw in the United States,” U.S. Institute of Peace, March 14, 2024; Bill Gertz, “Water Cannon Attack on Philippines

Navy Boat Raises Odds of U.S.-China Clash,” Washington Times, March 27, 2024; Seong Hyeon Choi, “Taiwan or

South China Sea: Which Is the Riskier Flashpoint for US-China Ties?” South China Morning Post, January 16, 2024;

Brad Lendon, “China-Philippines Maritime Standoff Escalating on Path That Could Drag US into Conflict, Analysts

Warn,” CNN, December 13, 2023. See also Agnes Chang, Camille Elemia, and Muyi Xiao, “China’s Risky Power Play

in the South China Sea,” New York Times, September 15, 2024.

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•

•

•

•

•

•

•

Have U.S. officials taken appropriate and sufficient steps to help reduce the risk

of maritime territorial disputes in the SCS and ECS escalating into conflicts?

Do the United States and Japan have a common understanding of potential U.S.

actions under Article IV of the U.S.-Japan Treaty on Mutual Cooperation and

Security (see Appendix B) in the event of a crisis or conflict over the Senkaku

Islands?

Do the United States and the Philippines have a common understanding of how

the 1951 U.S.-Philippines mutual defense treaty applies to maritime territories in

the SCS that are claimed by both China and the Philippines, and of potential U.S.

actions under Article IV of the treaty (see Appendix B) in the event of a crisis or

conflict over the territories?101 As noted earlier, in May 2023, the United States

and the Philippines released updated bilateral defense guidelines that, among

other things, clarified the circumstances under which U.S. forces would come to

the aid of the Philippines under the 1951 U.S.-Philippines mutual defense

treaty.102

Aside from public statements, what has the United States communicated to China

regarding potential U.S. actions under the two treaties in connection with

maritime territorial disputes in the SCS and ECS?

Has the United States correctly balanced ambiguity and explicitness in its

communications to various parties regarding potential U.S. actions under the two

defense treaties?

How do the two treaties affect the behavior of Japan, the Philippines, and China

in managing their territorial disputes? To what extent, for example, would they

help Japan or the Philippines resist potential PRC attempts to resolve the disputes

through intimidation, or, alternatively, encourage risk-taking or brinksmanship

behavior by Japan or the Philippines in their dealings with China on the disputes?

To what extent do they deter or limit PRC assertiveness or aggressiveness in their

dealings with Japan the Philippines on the disputes?

Has the DOD adequately incorporated into its planning crisis and conflict

scenarios arising from maritime territorial disputes in the SCS and ECS that fall

under the terms of the two treaties?

Whether United States Should Ratify UNCLOS

Another issue for Congress—particularly the Senate—is how competing strategically with China

in the SCS and ECS might affect the question of whether the United States should become a party

to the United Nations Convention on the Law of the Sea (UNCLOS).103 UNCLOS and an

associated 1994 agreement relating to implementation of Part XI of the treaty (on deep seabed

mining) were transmitted to the Senate on October 6, 1994.104 In the absence of Senate advice and

101 For an article bearing on this question, see GMA Integrated News, “DND: Armed attack should not be needed for

US to help in WPS,” GMA News Online, August 27, 2024.

102 See, for example, Felix K. Chang, “America and the Philippines Update Defense Guidelines,” Foreign Policy

Research Institute (FPRI), May 24, 2023.

103 For additional background information on UNCLOS, see Appendix C. For a press report regarding the debate about

whether the United States should become a party to the treaty, see Robert Delaney, “Why won’t the US, wary of

China’s ambitions in the South China Sea, join a UN agreement on ocean rights?” South China Morning Post, January

4, 2024.

104 Treaty Document 103-39.

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consent to adherence, the United States is not a party to UNCLOS or the associated 1994

agreement. During the 112th Congress, the Senate Foreign Relations Committee held four

hearings on the question of whether the United States should become a party to the treaty on May

23, June 14 (two hearings), and June 28, 2012.

Supporters of the United States becoming a party to UNCLOS argue or might argue one or more

of the following:

•

•

•

•

The treaty’s provisions relating to navigational rights, including those in EEZs,

reflect the U.S. position on the issue; becoming a party to the treaty would help

lock the U.S. perspective into permanent international law.

Becoming a party to the treaty would give the United States greater standing for

participating in discussions relating to the treaty—a “seat at the table”—and

thereby improve the U.S. ability to call on China to act in accordance with the

treaty’s provisions, including those relating to navigational rights, and to defend

U.S. interpretations of the treaty’s provisions, including those relating to whether

coastal states have a right under UNCLOS to regulate foreign military activities

in their EEZs.105

At least some of the ASEAN member states want the United States to become a

member of UNCLOS, because they view it as the principal framework for

resolving maritime territorial disputes.

Relying on customary international law to defend U.S. interests in these issues is

not sufficient, because it is not universally accepted and is subject to change over

time based on state practice.106

Opponents of the United States becoming a party to UNCLOS argue or might argue one or more

of the following:

•

•

China’s ability to cite international law (including UNCLOS) in defending its

position on whether coastal states have a right to regulate foreign military

activities in their EEZs107 shows that UNCLOS does not adequately protect U.S.

interests relating to navigational rights in EEZs; the United States should not help

lock this inadequate description of navigational rights into permanent

international law by becoming a party to the treaty.

The United States becoming a party to the treaty would do little to help resolve

maritime territorial disputes in the SCS and ECS, in part because China’s

maritime territorial claims, such as those depicted in the map of the nine-dash

line, predate and go well beyond what is allowed under the treaty and appear

rooted in arguments that are outside the treaty.

105 See, for example, Andrew Browne, “A Hole in the U.S. Approach to Beijing,” Wall Street Journal, May 20, 2014.

106 See, for example, Troy Bouffard, “Strategic Competition and the Case for UNCLOS,” Wilson Center, Polar Points

No. 30, June 4, 2024; Alex Willemyns, “White House Official Urges Senate to Ratify Law of the Sea,” Radio Free

Asia (RFA), December 7, 2023; Patricia Kine, “Signing Treaty Would Bolster US Against China, Russia Seapower:

Lawmaker,” Military.com, January 16, 2019.

107 For a discussion of China’s legal justifications for its position on the EEZ issue, see, for example, Peter Dutton,

“Three Disputes and Three Objectives,” Naval War College Review, Autumn 2011: 54-55. See also Isaac B. Kardon,

“The Enabling Role of UNCLOS in PRC Maritime Policy,” Asia Maritime Transparency Initiative (AMTI) (Center for

Strategic and International Studies [CSIS]), September 11, 2015.

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•

•

The United States can adequately support the ASEAN countries and Japan in

matters relating to maritime territorial disputes in the SCS and ECS in other

ways, without becoming a party to the treaty.

The United States can continue to defend its positions on navigational rights on

the high seas by citing customary international law, by demonstrating those rights

with U.S. naval deployments (including those conducted under the FON

program), and by having allies and partners defend the U.S. position on the EEZ

issue at meetings of UNCLOS parties.108

Legislative Activity in the 118th Congress

Legislative Activity for FY2025

FY2025 National Defense Authorization Act (NDAA) (H.R. 8070/S. 4638/H.R.

5009 /P.L. 118-159)

House

In H.R. 8070 as reported by the House Armed Services Committee (H.Rept. 118-529 of May 31,

2024) and passed by the House on June 14, 2024, Section 1757 states that “it is the policy of the

United States to reject as a violation of international law and United States sovereignty any

attempt by China’s Maritime Safety Administration to compel United States vessels to adhere to

any reporting requirements listed within China’s Maritime Traffic Safety Law,” with the policy to

be applied to “all maritime claims made by the People’s Republic of China that the United States

has rejected, to include virtually all of China’s claims within the Nine-Dash Line.”

Enacted

H.R. 5009/P.L. 118-159 of December 23, 2024, does not include Section 1757 of H.R. 8070 as

reported by the House Armed Services Committee.

Other Legislative Activity

Other bills and resolutions in the 118th Congress relating to the SCS and/or the ECS include but

are not necessarily limited to the following:

Introduced in House

•

•

•

H.R. 7757, a bill to amend the Securities Exchange Act of 1934 to require

disclosures with respect to certain financial risks relating to China, and for other

purposes.

H.R. 6597, the Indo-Pacific Treaty Organization Act.

H.R. 4659, a bill to promote free and fair elections, democracy, political

freedoms, and human rights in Cambodia, and for other purposes.

108 For articles providing general arguments against the United States becoming a party to UNCLOS, see Steven

Groves, “This Senate May Smile on Faulty Law of the Sea Treaty,” Heritage Foundation, March 19, 2021; Ted

Bromund, James Carafano, and Brett Schaefer, “7 Reasons US Should Not Ratify UN Convention on the Law of the

Sea,” Daily Signal, June 2, 2018.

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•

•

•

•

H.Res. 1412, a resolution condemning the China Coast Guard’s repeated

violations of international maritime law and aggression toward the Philippines,

Taiwan, Japan, and Malaysia.

H.Res. 1118, a resolution recognizing the importance of the U.S.-Japan alliance

and welcoming the visit of Prime Minister Kishida Fumio to the United States.

H.Res. 843, a resolution reaffirming the U.S.-Philippines alliance and

condemning China’s gray zone campaign in the SCS against the Philippines.

H.Res. 837, a resolution reaffirming the ties between the United States and the

Philippines.

Introduced in Senate

•

•

•

•

•

•

•

•

•

•

•

•

S. 5491, a bill to mobilize U.S. strategic, economic, and diplomatic tools to

confront the challenges posed by the PRC and set a positive agenda for U.S.

economic and diplomatic efforts abroad, and for other purposes.

S. 5131, a bill to advance a competitive strategy against the PRC, and for other

purposes.

S. 5089, a bill to impose sanctions with respect to the PRC maritime militia.

S. 4703, a bill to enhance the U.S.-Philippines partnership, and for other

purposes.

S. 4586, a bill to prevent the funding of malign activities of the Chinese

Communist Party though the sale of “A-Shares” on certain securities exchanges

controlled by the Chinese Communist Party by prohibiting the purchase, sale,

and ownership of such securities by United States investors, and for other

purposes.

S. 2331, a bill to promote free and fair elections, democracy, political freedoms,

and human rights in Cambodia, and for other purposes.

S. 591, the South China Sea and East China Sea Sanctions Act of 2023.

S. 151, a bill to amend the Securities Exchange Act of 1934 to address corrupt

practices of the Government of the People’s Republic of China, and for other

purposes.

S.Res. 834, a resolution reaffirming the Philippines’ claim over Second Thomas

Shoal and supporting the Filipino people in their efforts to combat aggression by

the PRC in the SCS.

S.Res. 816, a resolution recognizing the 73rd anniversary of the signing of the

U.S.-Philippines Mutual Defense Treaty and the strong U.S.-Philippines bilateral

security alliance in the wake of persistent and escalating aggression by the PRC

in the SCS.

S.Res. 626, a resolution recognizing the importance of the U.S.-Japan alliance

and welcoming the visit of Prime Minister Kishida Fumio to the United States.

S.Res. 466, a resolution calling upon the United States Senate to give its advice

and consent to the ratification of UNCLOS.

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Appendix A. Maritime Territorial and EEZ Disputes

in SCS and ECS

This appendix provides background information on maritime territorial and EEZ disputes in the

SCS and ECS that involve China. Other CRS reports provide additional and more detailed

information on these disputes.109

Maritime Territorial Disputes

China is a party to multiple maritime territorial disputes in the SCS and ECS, including in

particular the following (see Figure A-1 for locations of the island groups listed below):

•

•

•

•

a dispute over the Spratly Islands in the SCS, which are claimed entirely by

China, Taiwan, and Vietnam, and in part by the Philippines, Malaysia, and

Brunei, and which are occupied in part by all these countries except Brunei;

a dispute over Scarborough Shoal in the SCS, which is claimed by China,

Taiwan, and the Philippines, and controlled since 2012 by China; and

a dispute over the Paracel Islands in the SCS, which are claimed by China and

Vietnam, and occupied by China;

a dispute over the Senkaku Islands in the ECS, which are claimed by China,

Taiwan, and Japan, and administered by Japan.

The island and shoal names used above are the ones commonly used in the United States; in other

countries, these islands are known by various other names.110

These island groups are not the only land features in the SCS and ECS—the two seas feature

other islands, rocks, and shoals, as well as some near-surface submerged features. The territorial

status of some of these other features is also in dispute.111 There are additional maritime territorial

disputes in the Western Pacific that do not involve China.112 Maritime territorial disputes in the

SCS and ECS date back many years, and have periodically led to diplomatic tensions as well as

109 See CRS In Focus IF10607, China Primer: South China Sea Disputes, by Ben Dolven, Caitlin Campbell, and

Ronald O'Rourke; CRS In Focus IF12550, China-Philippines Tensions in the South China Sea, by Caitlin Campbell,

Ben Dolven, and William Piekos; CRS Report R44072, Chinese Land Reclamation in the South China Sea:

Implications and Policy Options, by Ben Dolven et al.; CRS Report R42930, Maritime Territorial Disputes in East

Asia: Issues for Congress, by Ben Dolven, Mark E. Manyin, and Shirley A. Kan; and CRS Report R43894, China's Air

Defense Identification Zone (ADIZ), by Ian E. Rinehart and Bart Elias.

110 China, for example, refers to the Paracel Islands as the Xisha islands, to the Spratly Islands as the Nansha islands, to

Scarborough Shoal as Huangyan island, and to the Senkaku Islands as the Diaoyu Islands.

111 For example, the Reed Bank, a submerged atoll northeast of the Spratly Islands, is the subject of a dispute between

China and the Philippines, and the Macclesfield Bank, a group of submerged shoals and reefs between the Paracel

Islands and Scarborough Shoal, is claimed by China, Taiwan, and the Philippines. China refers to the Macclesfield

Bank as the Zhongsha islands, even though they are submerged features rather than islands.

112 North Korea and South Korea, for example, have not reached final agreement on their exact maritime border; South

Korea and Japan are involved in a dispute over the Liancourt Rocks—a group of islets in the Sea of Japan that Japan

refers to as the Takeshima islands and South Korea as the Dokdo islands; and Japan and Russia are involved in a

dispute over islands dividing the Sea of Okhotsk from the Pacific Ocean that Japan refers to as the Northern Territories

and Russia refers to as the South Kuril Islands.

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U.S.-China Strategic Competition in South and East China Seas

confrontations and incidents at sea involving fishing vessels, oil exploration vessels and oil rigs,

coast guard ships, naval ships, and military aircraft.113

Figure A-1. Maritime Territorial Disputes Involving China

Island groups involved in principal disputes

Source: Map prepared by CRS using U.S. Department of State boundaries.

EEZ Dispute and U.S.-PRC Incidents at Sea

In addition to maritime territorial disputes in the SCS and ECS, China is involved in a dispute,

principally with the United States, over whether China has a right under international law to

regulate the activities of foreign military forces operating within China’s EEZ. The position of the

United States and most other countries is that while the United Nations Convention on the Law of

113 One observer states that “notable incidents over sovereignty include the Chinese attack on the forces of the Republic

of Vietnam [South Vietnam] in the Paracel Islands in 1974, China’s attack on Vietnamese forces near Fiery Cross Reef

[in the Spratly Islands] in 1988, and China’s military ouster of Philippines forces from Mischief Reef [also in the

Spratly Islands] in 1995.” Peter Dutton, “Three Dispute and Three Objectives,” Naval War College Review, Autumn

2011: 43. A similar recounting can be found in Department of Defense, Annual Report to Congress, Military and

Security Developments Involving the People’s Republic of China, 2011, p. 15.

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the Sea (UNCLOS), which established EEZs as a feature of international law, gives coastal states

the right to regulate economic activities (such as fishing and oil exploration) within their EEZs, it

does not give coastal states the right to regulate foreign military activities in the parts of their

EEZs beyond their 12-nautical-mile territorial waters.114

The position of China and some other countries (i.e., a minority group among the world’s nations)

is that UNCLOS gives coastal states the right to regulate not only economic activities, but also

foreign military activities, in their EEZs. In response to a request from CRS to identify the

countries taking this latter position, the U.S. Navy stated in 2012 that

countries with restrictions inconsistent with the Law of the Sea Convention [i.e., UNCLOS]

that would limit the exercise of high seas freedoms by foreign navies beyond 12 nautical

miles from the coast are [the following 27]:

Bangladesh, Brazil, Burma, Cambodia, Cape Verde, China, Egypt, Haiti, India, Iran,

Kenya, Malaysia, Maldives, Mauritius, North Korea, Pakistan, Portugal, Saudi Arabia,

Somalia, Sri Lanka, Sudan, Syria, Thailand, United Arab Emirates, Uruguay, Venezuela,

and Vietnam.115

Other observers provide different counts of the number of countries that take the position that

UNCLOS gives coastal states the right to regulate not only economic activities but also foreign

military activities in their EEZs. For example, one set of observers, in an August 2013 briefing,

stated that 18 countries seek to regulate foreign military activities in their EEZs, and that 3 of

these countries—China, North Korea, and Peru—have directly interfered with foreign military

activities in their EEZs.116

The dispute over whether China has a right under UNCLOS to regulate the activities of foreign

military forces operating within its EEZ appears to be at the heart of incidents between PRC and

U.S. ships and aircraft in international waters and airspace, including

114 The legal term under UNCLOS for territorial waters is territorial seas. This report uses the more colloquial term

territorial waters to avoid confusion with terms like South China Sea and East China Sea.

115 Source: Navy Office of Legislative Affairs email to CRS, June 15, 2012. The email notes that two additional

countries—Ecuador and Peru—also have restrictions inconsistent with UNCLOS that would limit the exercise of high

seas freedoms by foreign navies beyond 12 nautical miles from the coast, but do so solely because they claim an

extension of their territorial sea beyond 12 nautical miles. DOD states that

Regarding excessive maritime claims, several claimants within the region have asserted maritime

claims along their coastlines and around land features that are inconsistent with international law.

For example, Malaysia attempts to restrict foreign military activities within its Exclusive Economic

Zone (EEZ), and Vietnam attempts to require notification by foreign warships prior to exercising

the right of innocent passage through its territorial sea. A number of countries have drawn coastal

baselines (the lines from which the breadth of maritime entitlements are measured) that are

inconsistent with international law, including Vietnam and China, and the United States also has

raised concerns with respect to Taiwan’s Law on the Territorial Sea and the Contiguous Zone’s

provisions on baselines and innocent passage in the territorial sea. Although we applaud the

Philippines’ and Vietnam’s efforts to bring its maritime claims in line with the Law of the Sea

Convention, more work remains to be done. Consistent with the long-standing U.S. Freedom of

Navigation Policy, the United States encourages all claimants to conform their maritime claims to

international law and challenges excessive maritime claims through U.S. diplomatic protests and

operational activities.

(Department of Defense, Asia-Pacific Maritime Security Strategy, undated but released August

2015, pp. 7-8.)

116 Source: Joe Baggett and Pete Pedrozo, briefing for Center for Naval Analysis Excessive Chinese Maritime Claims

Workshop, August 7, 2013, slide entitled “What are other nations’ views?” (slide 30 of 47). The slide also notes that

there have been “isolated diplomatic protests from Pakistan, India, and Brazil over military surveys” conducted in their

EEZs.

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•

•

•

•

•

incidents in March 2001, September 2002, March 2009, and May 2009, in which

PRC ships and aircraft confronted and harassed the U.S. naval ships Bowditch,

Impeccable, and Victorious as they were conducting survey and ocean

surveillance operations in China’s EEZ;

an incident on April 1, 2001, in which a PRC fighter collided with a U.S. Navy

EP-3 electronic surveillance aircraft flying in international airspace about 65

miles southeast of China’s Hainan Island in the South China Sea, forcing the EP3 to make an emergency landing on Hainan Island;117

an incident on December 5, 2013, in which a PRC navy ship put itself in the path

of the U.S. Navy cruiser Cowpens as it was operating 30 or more miles from

China’s aircraft carrier Liaoning, forcing the Cowpens to change course to avoid

a collision;

an incident on August 19, 2014, in which a PRC fighter conducted an aggressive

and risky intercept of a U.S. Navy P-8 maritime patrol aircraft that was flying in

international airspace about 135 miles east of Hainan Island118—DOD

characterized the intercept as “very, very close, very dangerous”;119 and

an incident on May 17, 2016, in which PRC fighters flew within 50 feet of a

Navy EP-3 electronic surveillance aircraft in international airspace in the South

China Sea—a maneuver that DOD characterized as “unsafe.”120

Figure A-2 shows the locations of the 2001, 2002, and 2009 incidents listed in the first two

bullets above. The incidents shown in Figure A-2 are the ones most commonly cited prior to the

December 2013 involving the Cowpens, but some observers list additional incidents as well.121

117

For discussions of some of these incidents and their connection to the issue of military operating rights in EEZs, see

Raul Pedrozo, “Close Encounters at Sea, The USNS Impeccable Incident,” Naval War College Review, Summer 2009:

101-111; Jonathan G. Odom, “The True ‘Lies’ of the Impeccable Incident: What Really Happened, Who Disregarded

International Law, and Why Every Nation (Outside of China) Should Be Concerned,” Michigan State Journal of

International Law, vol. 18, no. 3, 2010: 16-22, accessed April 30, 2025, at http://papers.ssrn.com/sol3/papers.cfm?

abstract_id=1622943; Oriana Skylar Mastro, “Signaling and Military Provocation in Chinese National Security

Strategy: A Closer Look at the Impeccable Incident,” Journal of Strategic Studies, April 2011: 219-244; and Peter

Dutton, ed., Military Activities in the EEZ, A U.S.-China Dialogue on Security and International Law in the Maritime

Commons, Newport (RI), Naval War College, China Maritime Studies Institute, China Maritime Study Number 7,

December 2010, 124 pp. See also CRS Report RL30946, China-U.S. Aircraft Collision Incident of April 2001:

Assessments and Policy Implications, by Shirley A. Kan et al.

118 Source for location: Transcript of remarks by DOD Press Secretary Rear Admiral John Kirby at August 22, 2014,

press briefing, accessed April 30, 2025, at http://www.defense.gov/Transcripts/Transcript.aspx?TranscriptID=5493.

Chinese officials stated that the incident occurred 220 kilometers (about 137 statute miles or about 119 nautical miles)

from Hainan Island.

119 Source: Transcript of remarks by DOD Press Secretary Rear Admiral John Kirby at August 22, 2014, press briefing,

accessed April 30, 2025, at https://www.defense.gov/News/Transcripts/Transcript/Article/606919/department-ofdefense-press-briefing-by-admiral-kirby-in-the-pentagon-briefing/.

120 See, for example, Michael S. Schmidt, “Chinese Aircraft Fly Within 50 Feet of U.S. Plane Over South China Sea,

Pentagon Says,” New York Times, May 18, 2016; Thomas Gibbons-Neff, “Chinese Jets Intercept U.S. Recon Plane,

Almost Colliding Over South China Sea,” Washington Post, May 18, 2016; Idrees Ali and Megha Rajagopalan,

“Chinese Jets Intercept U.S. Military Plan over South China Sea: Pentagon,” Reuters, May 19, 2016; Jamie Crawford,

“Pentagon: ‘Unsafe’ Intercept over South China Sea,” CNN, May 19, 2016.

121 For example, one set of observers, in an August 2013 briefing, provided the following list of incidents in which

China has challenged or interfered with operations by U.S. ships and aircraft and ships from India’s navy: EP-3

Incident (April 2001); USNS Impeccable (March 2009); USNS Victorious (May 2009); USS George Washington

(July-November 2010); U-2 Intercept (June 2011); INS [Indian Naval Ship] Airavat (July 2011); INS [Indian Naval

Ship] Shivalik (June 2012); and USNS Impeccable (July 2013). (Source: Joe Baggett and Pete Pedrozo, briefing for

(continued...)

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Figure A-2. Locations of 2001, 2002, and 2009 U.S.-PRC Incidents at Sea and In Air

Source: Map prepared by CRS based on map shown on page 6 of Mark E. Redden and Phillip C. Saunders,

Managing Sino-U.S. Air and Naval Interactions: Cold War Lessons and New Avenues of Approach, Washington, Center

for the Study of Chinese Military Affairs, Institute for National Strategic Studies, National Defense University,

September 2012.

DOD stated in 2015 that

The growing efforts of claimant States to assert their claims has led to an increase in air

and maritime incidents in recent years, including an unprecedented rise in unsafe activity

by China’s maritime agencies in the East and South China Seas. U.S. military aircraft and

vessels often have been targets of this unsafe and unprofessional behavior, which threatens

the U.S. objectives of safeguarding the freedom of the seas and promoting adherence to

international law and standards. China’s expansive interpretation of jurisdictional authority

beyond territorial seas and airspace causes friction with U.S. forces and treaty allies

operating in international waters and airspace in the region and raises the risk of inadvertent

crisis.

Center for Naval Analysis Excessive Chinese Maritime Claims Workshop, August 7, 2013, slide entitled “Notable EEZ

Incidents with China,” (slides 37 and 46 of 47).) Regarding an event involving the Impeccable reported to have taken

place in June rather than July, see William Cole, “Chinese Help Plan For Huge War Game Near Isles,” Honolulu StarAdvertiser, July 25, 2013: 1. See also Bill Gertz, “Inside the Ring: New Naval Harassment in Asia,” July 17, 2013. See

also Department of Defense Press Briefing by Adm. Locklear in the Pentagon Briefing Room, July 11, 2013, accessed

April 30, 2025, at https://web.archive.org/web/20130712184831/http://www.defense.gov/transcripts/transcript.aspx?

transcriptid=5270.

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There have been a number of troubling incidents in recent years. For example, in August

2014, a Chinese J-11 fighter crossed direct

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