Senate Advances Iran War Powers Resolution as GOP Senator Cassidy Flips Vote

May 20, 2026

The Senate voted 50-47 on May 20, 2026 to advance a resolution forcing President Trump to end the war in Iran. Republican Sen. Bill Cassidy of Louisiana switched his vote to yes after losing his primary for renomination the weekend before. The war, known as Operation Epic Fury, has lasted more than 80 days. Democrats Rand Paul, Lisa Murkowski, and Susan Collins joined Democrats except John Fetterman in supporting the procedural motion.

Senate war powers vote

▪Every Democrat voted in favor of the war powers resolution except John Fetterman of Pennsylvania.
▪Three senators were absent from the May 20, 2026 vote: John Cornyn of Texas, Thom Tillis of North Carolina, and Tommy Tuberville of Alabama.
▪Republicans Rand Paul of Kentucky, Lisa Murkowski of Alaska, and Susan Collins of Maine voted to support the procedural motion on the Iran war powers resolution.
▪The Senate voted 50-47 on May 20, 2026 to advance a resolution to force President Donald Trump to end the war in Iran.

Cassidy vote flip

▪Sen. Bill Cassidy of Louisiana voted yes to advance the Iran war powers resolution on May 20, 2026, the first time Bill Cassidy voted yes after repeatedly voting no.
▪Sen. Bill Cassidy lost his primary for renomination on the weekend before May 20, 2026 after facing opposition from Trump.

Congressional authorization debate

▪Sen. Tim Kaine of Virginia introduced the Iran war powers resolution.
▪The Iran war powers resolution directs the President to remove United States Armed Forces from hostilities within or against Iran unless explicitly authorized by a declaration of war or a specific authorization for use of military force.
▪The war in Iran has lasted more than 80 days as of May 20, 2026.
▪Operation Epic Fury is the name of the military operation in Iran.

Democratic pressure strategy

▪Senate Minority Leader Chuck Schumer stated that Democratic pressure is causing Republicans to crack on the Iran war issue.
▪Senate Minority Leader Chuck Schumer stated that Democrats are breaking through Republicans' wall of silence on Trump's Iran war.

Resolution passage outlook

▪The Iran war powers resolution would need to pass the Republican-controlled House after passing the Senate.
▪If all three absent senators vote against the Iran war powers resolution, the vote would break 50-50 and the resolution would fail.
▪The timing of the final Senate vote on the Iran war powers resolution is unclear as of May 20, 2026.
▪The Iran war powers resolution would almost certainly face a presidential veto.

Perspective of Senate Democrats

▪Senate Minority Leader Chuck Schumer stated that Democrats are breaking through Republicans' wall of silence on Trump's Iran war.
▪Senate Minority Leader Chuck Schumer stated that Democratic pressure is causing Republicans to crack on the Iran war issue.