Senate Advances Resolution to Halt Military Action in Iran

The Senate on Tuesday advanced a resolution to halt military action in Iran after a surprise defection from Republican Sen. Bill Cassidy of Louisiana, dealing a blow to President Donald Trump's war effort.

The vote, though preliminary, shows that the Senate now could have the votes to force Trump to pull back the military from Iran or seek congressional approval for additional action.

Despite the War Powers Resolution advancing 50-47, it still has little chance of becoming law. It would need to pass a final vote in the Senate, clear the House and Trump would be almost certain to veto it. But the vote does show increasing headwinds to the war with Iran, especially as gas prices continue to soar ahead of the summer driving season and the 2026 midterms.

Cassidy, who failed to advance to a runoff against Trump-endorsed challenger Rep. Julia Letlow, R-La., in a primary election last week, is now in the final months of his term in the Senate. His vote indicates that he is now more willing to challenge Trump.

The war with Iran has now blown past the 60-day requirement under the War Powers Act for the president to seek the authorization of Congress for the use of military force. Though the Trump administration has challenged the law as unconstitutional, and claimed that a tenuous ceasefire in early April has stopped the clock by ceasing hostilities.

Republicans, who broadly opposed the measure, may have also been hindered by absences that allowed the measure to proceed. Several senators, including Sens. Thom Tillis, R-N.C., John Coryn, R-Texas and Tommy Tuberville, R-Ala., were absent from the vote.

Sen. John Fetterman, D-Pa., was the sole Democrat to vote against the measure, while 46 Republicans voted for it.