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

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.

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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.

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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

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