The Republican-led Senate on May 13 narrowly blocked a Democratic effort to force the Trump administration to allow Congress to vote on U.S. military involvement in the war with Iran, with three Republicans breaking ranks in the closest Senate vote yet on the issue.
The procedural vote to advance the resolution failed 50-49 after Pennsylvania Democratic Sen. John Fetterman joined most Republicans in opposition.
Sen. Lisa Murkowski, R-Alaska, voted in favor of the measure for the first time, joining Republican Sens. Rand Paul of Kentucky and Susan Collins of Maine alongside most Democrats. It marked the seventh failed Senate attempt this year to invoke the 1973 War Powers Resolution to curb the conflict.
The measure, introduced by Sen. Jeff Merkley, D-Ore., would have directed President Donald Trump to withdraw U.S. forces from hostilities with Iran unless Congress formally authorized continued military action through a declaration of war or other legislation. The resolution exempted operations conducted strictly in self-defense.
The vote came nearly two weeks after the expiration of the War Powers Resolution’s 60-day window requiring congressional authorization for continued military involvement. The Trump administration has argued that the major phase of hostilities ended with a fragile ceasefire reached in early April, eliminating the need for further approval from Congress.
Democrats and a small number of Republicans have disputed that claim, pointing to ongoing U.S. naval operations in the Strait of Hormuz and periodic exchanges involving Iranian forces as evidence the conflict remains active.
In a May 12 hearing with Defense Secretary Pete Hegseth, Sen. Murkowski said “where there is confusion is when the President says hostilities have ended,” adding: “It does not appear that hostilities have ceased.”
After the vote, she issued a statement on X, saying that she opposed efforts “to redefine ‘hostilities’ in ways that allow the president to wage war indefinitely without seeking congressional approval.”
Today, the Senate voted on a resolution directing the president to remove U.S. Armed Forces from hostilities in Iran, the eighth such resolution on this matter. I voted against the previous seven resolutions because I believed an abrupt withdrawal would endanger American forces…
— Sen. Lisa Murkowski (@lisamurkowski) May 13, 2026
Merkley also argued the administration was attempting to sidestep constitutional war powers requirements by characterizing the conflict as dormant despite continuing military activity.
“Both sides are engaged in a daily war,” Merkley said on the Senate floor. “It is a war by every definition.”
Republican leaders defended Trump’s handling of the conflict and said the ceasefire had substantially halted combat operations.
“The major fighting has halted,” said Sen. John Barrasso of Wyoming, the Senate’s No. 2 Republican, accusing Democrats of trying to undermine the President during sensitive negotiations.
Democrats said they plan to continue forcing weekly votes on the issue as pressure grows over the political and financial costs of the war ahead of the midterm elections.