The War Powers Resolution, explained: the 1973 law at the center of the Iran war and the Hegseth impeachment

A law passed in the final months of the Vietnam War has become one of the most cited pieces of legislation in Washington this fall. The War Powers Resolution of 1973 sits at the heart of the House vote on impeaching Defense Secretary Pete Hegseth and of Democrats’ plans to force an end to the war with Iran.

Here is what it says, what it does not say and why it has rarely worked the way its authors intended.

Who gets to start a war?

The Constitution splits the job. Article I, Section 8 gives Congress the power to declare war, raise and support armies and fund the military. Article II, Section 2 makes the president commander in chief. For most of American history, the line between the two was argued over rather than settled.

Congress has formally declared war only 11 times, most recently in World War II. Every major conflict since, from Korea to Iraq, was fought under some combination of presidential authority, congressional authorizations and funding votes.

What the 1973 law requires

Congress passed the War Powers Resolution over President Richard Nixon’s veto in November 1973, after years of fighting in Southeast Asia without a declaration of war. Its core requirements, codified in Chapter 33 of Title 50 of the U.S. Code, are:

Requirement	What it means
Consult	The president should consult Congress “in every possible instance” before sending forces into hostilities.
Report within 48 hours	The president must notify Congress in writing within 48 hours of introducing forces into hostilities or imminent hostilities.
60-day clock	Unless Congress declares war or authorizes the use of force, the president must end the use of forces within 60 days.
30-day extension	The deadline can stretch another 30 days if needed to withdraw troops safely.
Expedited votes	Resolutions to remove forces get fast-track procedures so leaders cannot simply bury them.

Why presidents keep getting around it

Every president since Nixon has questioned whether the law is constitutional, while usually filing the required reports anyway. In practice, they have found several ways around the 60-day clock.

Defining “hostilities” narrowly

Administrations have argued that some operations, such as air campaigns with little risk to U.S. troops, do not count as hostilities. The Obama administration made that argument about the 2011 air war in Libya.

The Supreme Court’s 1983 ruling

The original law let Congress order a withdrawal with a concurrent resolution, which does not go to the president. In INS v. Chadha in 1983, the Supreme Court struck down that kind of legislative veto in another context, casting doubt on the provision. Since then, Congress has generally relied on joint resolutions, which the president can veto.

The veto

That is the real limit. A joint resolution ordering an end to hostilities needs a two-thirds vote in both chambers to survive a veto. President Donald Trump vetoed war powers resolutions on Yemen in 2019 and on Iran in 2020, and Congress could not override either.

How it applies to the Iran war

The current war began on Feb. 28 with U.S. and Israeli strikes on Iran. Congress has not declared war on Iran or passed a specific authorization for this conflict.

Lawmakers have tried to use the 1973 law repeatedly:

February: Days before the war began, House Democratic leaders announced they would force a vote on a bipartisan resolution from Reps. Ro Khanna and Thomas Massie requiring the president to come to Congress before using force against Iran, according to a statement from House Democratic leaders.
June: Congress passed a concurrent resolution, with some Republican support, directing the president to withdraw U.S. forces from hostilities against Iran or seek congressional approval, The Conversation noted. Because of the Chadha ruling, its legal force is disputed.
Since then: Other war powers votes have passed but have been largely symbolic, NPR reported.

Why it is in the Hegseth impeachment

Three of the eight articles of impeachment Rep. Thomas Massie filed against Hegseth accuse him of waging the Iran war in violation of different sections of the War Powers Resolution, ABC News reported. The argument is that the 60-day limit expired months ago without congressional authorization.

Supporters of the administration answer that the president has inherent authority as commander in chief to defend U.S. forces and allies, and that a defense secretary carrying out the president’s orders is not personally liable for disputes over war powers. That is a central question the vote forces lawmakers to answer.

What a Democratic Congress can do with it

From January, Democrats will control both chambers. They can schedule war powers votes freely, but a Trump veto would still require two-thirds to override. Critics on both the left and the libertarian right argue the stronger tool is money: cutting off funds for hostilities in a spending bill, Reason argued. That path carries political risk, since it can be framed as abandoning troops in the field.

The fight over the 1973 law is, in the end, a fight over the original constitutional question: when the president goes to war, what can Congress actually do to stop it?

Key dates

Nov. 7, 1973: Congress overrides Nixon’s veto and enacts the War Powers Resolution.
1983: INS v. Chadha casts doubt on concurrent-resolution withdrawals.
2011: Obama administration says the Libya air war does not amount to hostilities under the law.
2019 and 2020: Trump vetoes war powers resolutions on Yemen and Iran.
Feb. 28, 2026: U.S. and Israeli strikes on Iran begin.
November 2026: War powers violations form the basis of impeachment articles against Hegseth.