Lisa Murkowski

Three Republican senators broke with Senate GOP leadership Wednesday and voted with Democrats to advance a resolution aimed at halting U.S. military hostilities involving Iran unless Congress formally authorizes further action.

Sens. Lisa Murkowski, R-Alaska, Susan Collins, R-Maine, and Rand Paul, R-Ky., joined nearly every Senate Democrat in supporting the resolution under the 1973 War Powers Act, though the effort still failed by a 49-50 vote, according to The Hill.

Sen. John Fetterman, D-Pa., was the lone Democrat to vote against advancing the measure.

The resolution sought to require President Donald Trump to remove U.S. armed forces from hostilities involving Iran absent explicit congressional approval.

Several Republicans who previously voiced concerns about presidential war powers still voted against advancing the measure, including Sens. John Curtis, R-Utah, Thom Tillis, R-N.C., Josh Hawley, R-Mo., and Todd Young, R-Ind.

Senate Majority Whip John Barrasso, R-Wyo., sharply criticized Democrats for pushing the resolution, arguing Republicans should stand behind Trump as tensions with Iran continue.

"For decades, American presidents have pledged that Iran would not get a nuclear weapon. Only President Trump has had the courage and the strength to keep his word," Barrasso said.

Senate Majority Leader John Thune, R-S.D., also urged Republicans to oppose the measure, arguing it would undermine Trump while he was overseas meeting with Chinese President Xi Jinping.

"I think right now the president is overseas, he’s negotiating with the Chinese on a whole range of issues, some of which bear on national security, and I think it would be best if everybody hung together and supported the president," Thune said before the vote.

The Senate vote came after the expiration of the 60-day period under the War Powers Act, during which a president can engage militarily without congressional authorization.

Trump notified Congress on March 2 regarding the use of force against Iran, starting the clock under the law.

Republicans argued the timeline had effectively paused because the United States and Iran entered a ceasefire in early April.

Trump stated in a May 1 letter to Congress that the ceasefire extended the period allowing military action without additional approval.

"On April 7, 2026, I ordered a 2-week ceasefire. The ceasefire has since been extended. There has been no exchange of fire between United States Forces and Iran since April 7, 2026," Trump wrote.

Democrat supporters of the resolution disputed that interpretation.

Sen. Tim Kaine, D-Va., argued hostilities were still ongoing despite the ceasefire.

"There is a war that’s going on, just a cessation of the bombing campaign," Kaine told reporters before the vote.

Collins previously explained her opposition to continuing military action without a clearly defined objective.

"Further military action against Iran must have a clear mission, achievable goals, and a defined strategy for bringing the conflict to a close," Collins said in an earlier statement.