Does the Constitution allow Trump to attack Iran?

UPDATED – March 2026

President Trump’s decision to attack Iran in February 2026 has again called into question whether the President’s action are unconsitutional. In the strikes on the 28th February, USA and Israeli forces killed the Iranian Supreme Leader Ali Hosseini Khamenei whilst inflicting considerable damage on the Iranian nuclear programme.

As soon as the attacks begun, members of Congress were demanding a War Powers Resolution be passed to demand the President halt further attacks. Even if Congress were to support a War Powers Resolution, the President would veto it and it is unlikely that there would be a two thirds majority to over-ride that veto.

Similarly, in January, Congress voted upon a War Powers Resolution, in an attempt to stop further action by President Trump against Venezuela. 5 Republicans Senators voted in favour of advancing a War Powers Resolution on that occassion with one, Josh Hwley stating that “To me, this is all about going forward…If the president should determine, ‘You know what? I need to put troops on the ground of Venezuela,’ I think that would require Congress to weigh in.”

Despite his initial words, Senator Hawley decided to vote against the War Powers Resolution when it came to a final vote. Hawley said he had been convinced by the President that no troops would be on the ground in Venezuela and this helped to ensure he changed his vote.

As mentioned previously, the War Powers Act is an exceedingly limited tool through which Congress might restrain the foreign policy of the US President. Votes on the War Powers Act have become symbolic, a way of Congress showing opposition to the President, rather then a meaningful weapon they might use.

President Trump’s decision to launch missile strikes against Iran’s nuclear capabilities in June 2025 has been seen by some as a violation of Congress’ constitutional power to declare war. Were the missile strikes against Iran a declaration of war? Historically, many have interpreted missile strikes, which have been carried on different targets by all Presidents since the 1980s, as not constituting a declaration of war. The line has instead always been drawn on soldiers being used in combat.

Nonetheless, Democrats in the Senate put forward a War Powers Resolution which, had it passed, would have required the President to notify it before any further attacks against Iran. The Senate rejected the resolution 53-47, with the vote going along party lines except for the Democrat, John Fetterman who voted no and the Republican Rand Paul who voted yes.

Trump’s attack on Iran and Congress’ failure to pass the War Powers Resolution are further demonstration of the power that Congress has ceded to the President on foreign policy.