Defense Primer: Strategic Nuclear Forces

Updated April 1, 2026

Defense Primer: Strategic Nuclear Forces

The Department of Defense (DOD)—which is “using a

secondary Department of War designation” under

Executive Order 14347 dated September 5, 2025—is in the

process of modernizing U.S. strategic nuclear forces. This

modernization effort includes numerous DOD major

defense acquisition programs, some of which are annually

assessed by the Government Accountability Office, and

warhead modernization programs implemented by the

National Nuclear Security Administration (NNSA), a semiautonomous Department of Energy agency. In 2025, the

Congressional Budget Office estimated that U.S. programs

to operate and modernize nuclear forces would cost $946

billion over the next 10 years. DOD stated that its FY2026

budget request includes “~$60 billion across the nuclear

enterprise to sustain nuclear forces and fund a major

recapitalization across all three legs of the nuclear triad.”

Some Members of Congress have shown strong interest in

conducting oversight of U.S. nuclear modernization efforts.

The Nuclear Triad

Since the early 1960s, the United States has maintained a

“triad” of strategic nuclear delivery vehicles. These include

long-range land-based intercontinental ballistic missiles

(ICBMs), long-range submarine-launched ballistic missiles

(SLBMs) on strategic nuclear submarines (SSBNs), and

long-range heavy bombers. The U.S. nuclear warhead

stockpile has decreased in number as the United States

changed nuclear planning requirements after the end of the

Cold War and complied with arms control agreements.

Some nongovernmental organizations have provided annual

estimates of warheads deployed on U.S. nuclear forces.

Until February 5, 2026, U.S. strategic forces were limited

by the 2011 U.S.-Russian New START treaty. Table 1

displays U.S. nuclear forces, as of September 1, 2022,

accountable under that treaty. The United States had 1,419

warheads deployed on 662 missiles and bombers as of

March 1, 2023, according to a more recent State

Department fact sheet.

Table 1. U.S. Strategic Nuclear Forces in 2022

System

Minuteman III

ICBM

Trident (D-5)

SLBM

B-52 bombers

B-2 bombers

Total

a.

The treaty attributes one warhead to each deployed bomber,

although each could carry up to 20 bombs or cruise missiles.

Rationale for the Triad

Early in the Cold War, the United States developed three

types of nuclear delivery vehicles, in large part because

each of the military services wanted part of the U.S. nuclear

arsenal. Eventually, DOD came to argue that different

basing modes’ complementary strengths could enhance

nuclear deterrence. The 2010 Nuclear Posture Review

(NPR), a periodic assessment of U.S. nuclear policy,

summarized the post-Cold War evolution of this thinking:

[SSBNs] and the SLBMs they carry represent the

most survivable leg of the U.S. nuclear Triad.…

Single-warhead ICBMs contribute to stability, and

like SLBMs are not vulnerable to air defenses.

Unlike ICBMs and SLBMs, bombers can be visibly

deployed forward, as a signal in crisis to strengthen

deterrence of potential adversaries and assurance of

allies and partners.

The U.S. government has reaffirmed the value of the

nuclear triad and the importance of its modernization in a

series of NPRs. The Obama Administration stated in the

2010 NPR that the unique characteristics of each leg of the

triad were important to “maintain strategic stability at

reasonable cost, while hedging against potential technical

problems or vulnerabilities.” The Trump Administration

stated in the 2018 NPR that “the triad’s synergy and

overlapping attributes help ensure the enduring

survivability of our deterrence capabilities against attack

and our capacity to hold a range of adversary targets at risk

throughout a crisis or conflict.” The Biden Administration’s

2022 NPR argued that “maintaining a modern triad

possessing these attributes—effectiveness, responsiveness,

survivability, flexibility, and visibility—ensures that the

United States can withstand and respond to any strategic

attack, tailor its deterrence strategies as needed, and assure

Allies in support of our extended deterrence commitments.”

Current Forces and Modernization Plans

Total

Launchers

454

Deployed

Launchers

396

Warheads

396

280

220

981

46

20

800

33

10

659

33a

10a

1,420

Source: U.S. Department of State, “New START Treaty Aggregate

Numbers of Strategic Offensive Arms,” September 1, 2022.

ICBMs

Before implementing the New START Treaty, the United

States deployed 450 Minuteman III ICBMs at Air Force

bases in Wyoming, Montana, and North Dakota. Under

New START, the number has declined to 400 deployed

missiles, although the Air Force has retained all 450 silo

launchers. While each Minuteman III missile originally

carried three warheads, the United States has deployed the

missile with a single warhead in order to comply with New

START levels. The Air Force has completed life extension

programs (LEPs) to improve the accuracy and reliability of

the Minuteman III.

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Defense Primer: Strategic Nuclear Forces

The Air Force also is developing a new ICBM, the Sentinel,

previously known as the Ground-Based Strategic Deterrent

(GBSD), which will replace all Minuteman III ICBMs. The

Air Force currently plans to acquire 659 missiles to support

testing and deployment. The NNSA is developing a new

W87-1 warhead to deploy on the Sentinel. In 2024, DOD

conducted a congressionally mandated review of the

Sentinel program due to cost overruns and delays. For

FY2026, the Trump Administration requested $2.7 billion

in discretionary funding and assumed $1.5 billion in

mandatory funding from FY2025 reconciliation legislation

(P.L. 119-21), commonly referred to as the One Big

Beautiful Bill Act, for the Sentinel in the DOD budget. The

NNSA budget request for FY2026 included $649 million

for the W87-1 warhead. (See CRS In Focus IF11681,

Defense Primer: LGM-35A Sentinel Intercontinental

Ballistic Missile.)

of” 100 of the new bomber, which is currently in testing

and initial production. The Air Force included $5.8 billion

in discretionary funding and assumed $4.5 billion in

mandatory funding from FY2025 reconciliation legislation

for this new bomber in its FY2026 budget request. (See

CRS In Focus IF12945, U.S. Strategic Bombers.)

SLBMs

The United States currently has 14 Trident (Ohio-class)

SSBNs. Under New START, each submarine has carried

20, rather than the original 24, missiles. Using treaty

counting rules, the 14 submarines counted as a total of 280

deployed and nondeployed launchers, with a maximum of

240 deployed launchers and around 1,000 warheads

counting on 12 operational boats (assuming two submarines

are in overhaul). The Navy operates SSBN bases in

Washington and Georgia. The Navy is procuring 12 new

Columbia-class submarines that feature 16 SLBM tubes

each. The lead boat was supposed to begin patrols in

FY2031, but the Navy has stated that it is delayed. The

Navy requested $9.6 billion in discretionary funding and

assumed $1.9 billion in mandatory funding from FY2025

reconciliation legislation for the Columbia-class submarine

in its FY2026 budget submission. (See CRS Report

R41129, Navy Columbia (SSBN-826) Class Ballistic

Missile Submarine Program: Background and Issues for

Congress.)

The Air Force is planning to replace the aging air-launched

cruise missiles carried by B-52 bombers with a new

advanced Long Range Standoff (LRSO) cruise missile. The

Air Force plans to buy a total of 1,087 missiles and has

included $1.1 billion for the missile in its FY2026 budget

request. NNSA also is conducting an LEP on the W80

warhead to provide a warhead for the LRSO.

U.S. SSBNs carry the D-5 SLBMs. The Navy conducts

LEPs so that the missile remains capable and reliable

throughout the deployment of the new Columbia-class

SSBN. The Navy’s FY2026 budget request included $3.7

billion for the D5LE and D5LE2 programs.

NNSA has conducted an LEP for the W76 warhead, which

is carried by most Trident missiles, and provided a small

number of low-yield warheads, known as the W76-2, to the

Navy in FY2020. NNSA also is improving the safety and

reliability of the W88 warhead, which is carried by a

portion of the fleet, and has initiated work on the W93

warhead, which is to eventually deploy on D-5 missiles.

Heavy Bombers

The Air Force has 20 B-2 bombers based in Missouri. The

B-2 can carry B61 and B83 nuclear gravity bombs, but it is

not equipped to carry cruise missiles. The Air Force

maintains 74 B-52H bombers at bases in Louisiana and

North Dakota. The B-52 is equipped to carry nuclear airlaunched cruise missiles. The B-2 and B-52 bombers also

can carry conventional weapons. The Air Force also is

acquiring a new B-21 Raider bomber for conventional and

nuclear missions; the service plans to “procure a minimum

The United States has a number of B61 and B83 gravity

bombs. NNSA has conducted an LEP on several variants of

the B61 to produce a single variant, known as the B61-12.

DOD and NNSA have planned to retire the B83, the largest

bomb remaining in the U.S. arsenal. The 2018 NPR

supported retaining the B83, but the 2022 NPR announced

retirement of the weapon. In 2023, DOD announced that

NNSA would develop a new B61-13 bomb to give the

President “additional options against certain harder and

large-area military targets” as it “works to retire” the B83.

Nuclear Command, Control, and Communications

The United States also is modernizing its nuclear command,

control, and communications (NC3) architecture. (See CRS

In Focus IF11697, Defense Primer: Nuclear Command,

Control, and Communications (NC3).)

Employment Planning and Force Sizing

The President, the Secretary of Defense, the Chairman of

the Joint Chiefs of Staff, the Commander of U.S. Strategic

Command (STRATCOM), and other stakeholders in the

U.S. government and military participate in a process of

planning for the potential employment of U.S. nuclear

forces that, inter alia, contributes to determining an

appropriate size and mix of U.S. strategic and nonstrategic

nuclear forces to meet U.S. national security requirements.

The 2023 report of the Congressional Commission on the

U.S. Strategic Posture argued that the current U.S. nuclear

forces modernization plan (the so-called program of record,

or POR) was “necessary, but not sufficient” because it did

not account for an emerging environment where the United

States will face two nuclear peers—Russia and the People’s

Republic of China (PRC).

DOD’s 2024 Report on the Nuclear Employment Strategy

of the United States stated that the United States “confronts

multiple nuclear competitors” and required that planning

account for “new deterrence challenges.” It also stated that

the United States may need to “adapt current U.S. force

capability, posture, composition, or size” and that DOD will

“continuously evaluate” the need to make such adjustments.

Following the February 2026 expiration of the New START

treaty, some experts have debated whether and when the

United States should consider adding (or uploading)

warheads to existing ICBMs, SLBMs, and bombers.

Anya L. Fink, Analyst in U.S. Defense Policy

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Defense Primer: Strategic Nuclear Forces

IF10519

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