The U.S. Senate fell one vote short of advancing a resolution to direct the removal of U.S. Armed Forces from hostilities in or against Iran, rejecting a motion to discharge S.J.Res. 163 by a margin of 49-50 on Wednesday.

Senator Lisa Murkowski of Alaska became the third Republican to join Democrats in supporting the measure after previously opposing it, marking a rare shift in Senate dynamics. She was joined by Senators Susan Collins of Maine and Rand Paul of Kentucky. The sole Democrat to vote against the motion was Senator John Fetterman of Pennsylvania, while Senator Pete Ricketts of Nebraska did not cast a ballot.

The joint resolution, led by Senator Jeff Merkley of Oregon, would have required the president to withdraw forces from Iran hostilities unless Congress explicitly authorized such action through a declaration of war or specific military force authorization. The vote followed a 60-day War Powers window that expired without the administration providing clarity on the legal basis for continued operations in the region.

Defense Secretary Pete Hegseth told Murkowski that the administration believes it retains all necessary authority under Article II of the Constitution if President Trump decides to resume strikes. However, Murkowski argued that deployed troops and warships made it difficult to accept that hostilities had truly ended following the April 7 ceasefire.

The Senate roll call recorded on May 13, 2026, showed the motion was rejected with one senator absent. The vote underscored growing constitutional pressure from both parties as the administration defends its position that the War Powers clock stopped after the ceasefire, while senators push for Congress to retain oversight of ongoing military postures in the region.