# War Powers Issues: U.S. Use of Military Force Against Iran

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URL: https://www.frixlaw.com/law-library/documents/crs%3AIN12577

## Record

- **Collection:** Congressional research report
- **Document type:** Insight
- **Published:** June 23, 2025
- **Citation:** IN12577

## Text

INSIGHTi

War Powers Issues: U.S. Use of Military Force
Against Iran
June 23, 2025
The War Powers Resolution (WPR), among other things, requires the President to inform Congress of
certain deployments abroad and the “introduction of United States Armed Forces into hostilities,”
providing expedited procedures for congressional consideration of authorization or disapproval of such
presidential action. In connection with the intensified Israel-Iran conflict, U.S. air and naval forces at
President Trump’s direction struck Iranian nuclear facilities on June 21. Some Members of Congress have
questioned the President’s authority to use military force against Iran, asserted Congress’s constitutional
role in such decisions, and criticized the President’s decision to act without seeking authorization from
Congress. Some Members have stated the President possesses constitutional authority for such action and
supported the President’s decision.
The President had previously ordered additional forces to the Middle East in response to the conflict, and
U.S. forces in Israel and international waters have reportedly defended Israel by intercepting Iranian
missiles. U.S. forces in the region are based and otherwise deployed within range of Iranian military
strike capabilities, and have been targeted in at least one Iranian military response to date, though no
casualties were reported.

Presidential Reporting Under the War Powers
Resolution
The WPR requires presidential consultation with and notification to Congress concerning decisions to use
U.S. Armed Forces. Pursuant to Section 4, the President must notify the Speaker of the House and the
President pro tempore of the Senate within 48 hours after U.S. forces “are introduced” into active or
imminent hostilities, or otherwise into a foreign nation while equipped for combat. The notification must
describe the “circumstances necessitating” the introduction, the “estimated scope and duration of the
hostilities or involvement,” and the “constitutional and legislative authority” for the decision. The
President is required to “provide such other information as the Congress may request” in connection with
a notification.
Congressional Research Service
https://crsreports.congress.gov
IN12577
CRS INSIGHT
Prepared for Members and
Committees of Congress

Congressional Research Service

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On June 23, President Trump submitted a WPR notification explaining the June 21 Iran strikes, asserting
constitutional authority for the action based on his role “as Commander in Chief and Chief Executive and
pursuant to [his] constitutional authority to conduct United States foreign relations.” He did not cite any
statutory authority. He noted the possibility of further uses of military force “to address further threats or
attacks.”
Previous WPR notifications on multiple occasions since 2019 have described U.S. use of military force
against Iranian forces and U.S. operations to defend against Iranian military threats and actions. Other
U.S. and Iranian actions have been reported but not included in publicly available WPR notifications.

“Hostilities” Under the WPR
The WPR contains provisions circumscribing the President’s authority to introduce U.S. Armed Forces
into “hostilities.” While the executive branch might attempt to foreclose congressional findings of
hostilities, the WPR seems to seek the involvement of Congress to “insure that the collective judgment of
both the Congress and the President will apply.”
The term “hostilities” is not defined in the WPR. According to an executive branch interpretation, the
term applies only to active exchanges of fire between U.S. and “opposing units of hostile forces,” and
U.S. use of military force does not amount to “hostilities” under the WPR if military force is “limited in
nature, scope, and duration,” based on various factors. The House report accompanying the WPR, in
contrast, states that the term includes not only the use of military force by and against U.S. Armed Forces
but also “encompasses a state of confrontation in which no shots have been fired but where there is a clear
and present danger of armed conflict.” Such hostilities are “imminent” when “there is a clear potential
either for such a state of confrontation or for actual armed conflict.”
In the current situation concerning Iran, determining “hostilities” might depend on interpretation of the
term as well as the breadth of information considered. If hostilities exist only during active exchanges of
fire, it could be argued that hostilities would end as soon as an exchange of fire ceases, which may have
already occurred. It could also be argued that hostilities have existed during the overall period when uses
of force have occurred intermittently in the context of an ongoing state of confrontation between U.S. and
Iranian forces, possibly extending back several years and continuing at present.

Presidential Authority to Conduct Hostilities
The President has stated that he has the authority to direct the use of military force against Iran. This
assertion seems to align with previous executive-branch interpretation asserting Article II authority to use
military force in the national interest and when such action would not “rise to the level of a war in the
constitutional sense.” According to the WPR, the President’s exclusive constitutional powers to introduce
U.S. Armed Forces into hostilities are limited to defense of the United States or its Armed Forces against
an armed attack creating a “national emergency”; continuing hostilities must receive congressional
authorization.
Further attacks by Iran, if they were to occur, might prompt defensive U.S. military action including
further use of military force. The WPR seems to require the President to submit to Congress for approval
or disapproval any deployments of U.S. Armed Forces resulting in hostilities, whether such hostilities are
offensive or defensive in nature.

Congressional Research Service

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Possible Congressional Employment of WPR Measures
Congress may choose to authorize or terminate the use of Armed Forces with regard to any hostilities
involving Iran; the WPR requires presidential consultation and reporting to inform that choice. The WPR
empowers Congress to consider legislative war powers measures whether or not the President engages in
the process. Congress may request information from the Administration that directly addresses war
powers authorities.
If Congress were to find that U.S. forces are engaged in ongoing unauthorized hostilities with Iranian
forces, the WPR and related legislation provide expedited procedures to consider authorizing, or requiring
immediate removal of U.S. forces from, such hostilities. Privileged measures have been introduced in
both Chambers to require the removal of U.S. forces from hostilities with Iran. If Congress does not adopt
either measure within 60 days, the President must terminate the use of U.S. forces related to any required
notification without further congressional action, subject to a 30-day extension if necessary for orderly
removal of forces. According to the WPR’s provisions, this 60-day period is not a grant of authority to
conduct hostilities, but instead serves as a window for Congress to decide whether to cure the
unauthorized use of the military.

Author Information
Matthew C. Weed
Specialist in Foreign Policy Legislation

Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff
to congressional committees and Members of Congress. It operates solely at the behest of and under the direction of
Congress. Information in a CRS Report should not be relied upon for purposes other than public understanding of
information that has been provided by CRS to Members of Congress in connection with CRS’s institutional role.
CRS Reports, as a work of the United States Government, are not subject to copyright protection in the United
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IN12577 · VERSION 2 · NEW

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/crs%3AIN12577. Public record. Not legal advice.
