Senate Republicans on Wednesday again blocked Democratic legislation that would halt President Donald Trump’s war with Iran, but the number of GOP senators voting against the war grew in a sign of deepening unease within the president’s own party. Republican Senator Lisa Murkowski of Alaska voted against the war for the first time since hostilities began at the end of February, joining a small but growing caucus of Republican dissenters as the conflict enters its third month with no clear resolution.
Murkowski’s Flip Signals Shifting GOP Dynamics
Murkowski’s decision to vote against the war marked a significant shift for the Alaska senator, who had previously supported the administration’s military posture. Her defection came one day after Defense Secretary Pete Hegseth told lawmakers during a hearing on Tuesday that the U.S. could resume attacking Iran without seeking congressional approval, asserting the administration has “all the authorities necessary” to continue the campaign. Murkowski voiced direct skepticism about that argument, pointing to the troops and warships deployed to the Persian Gulf region. “It doesn’t appear that hostilities have ended,” she stated plainly, underscoring the widening gap between the White House’s legal position and the reality on the ground.
“It doesn’t appear that hostilities have ended.”
— Senator Lisa Murkowski (R-Alaska), Capitol hearing, May 2026
Two other Republicans, Senators Susan Collins of Maine and Rand Paul of Kentucky, also voted against the war, as they had done in previous votes. But Murkowski’s addition to their ranks suggested the dissent is expanding beyond the party’s traditional libertarian and moderate wings into the broader Republican conference — a development that has alarmed party leaders even as they maintain public support for the administration’s posture.
White House Circumvents Congress as Democrats Force Repeated Votes
The White House has asserted that it does not need congressional authorization for the war and has circumvented legal requirements under the War Powers Resolution of 1973, which mandates that presidents obtain congressional approval after 60 days of engaging in a conflict. The administration claims it has “terminated” hostilities with Iran because the U.S. has entered a ceasefire — a legal interpretation that has drawn sharp criticism from constitutional scholars and lawmakers in both parties, who note that U.S. military assets remain on high alert and commercial shipping through the Strait of Hormuz remains severely disrupted.
Democrats, led by Senator Tim Kaine of Virginia, have responded by forcing repeated votes on war powers resolutions to build political pressure on the president. Kaine predicted before Wednesday’s vote that the Senate would eventually demand an end to the conflict.
“There will be a day — and it might be soon, I believe — where this Senate will say to the president, ‘Stop this war.'”
— Senator Tim Kaine (D-Virginia), Senate floor, May 13, 2026
Senator Jeff Merkley, an Oregon Democrat who sponsored Wednesday’s resolution, told reporters after the vote that he believes there is an “erosion of support, erosion of enthusiasm, an increase in skepticism” about the war from Republicans. Democrats plan to continue forcing weekly votes on war powers resolutions and are looking ahead to the annual defense authorization legislation as another avenue to impose limitations on Trump’s military actions.
Republican Leadership Backs War as Gasoline Prices Fuel Electoral Anxiety
Republican leadership has continued to back the war, arguing that the stalemate in the Strait of Hormuz puts more economic pressure on Iran than on the United States. “Iran’s economy is on life support. Its leadership is eliminated,” said Senator John Barrasso, the No. 2 Republican in leadership, during a floor speech Wednesday. He accused Democrats of trying to undermine Trump by forcing the vote just as the president arrived in China for a high-stakes summit with Chinese leader Xi Jinping.
“Iran’s economy is on life support. Its leadership is eliminated.”
— Senator John Barrasso (R-Wyoming), Senate floor, May 13, 2026
But even as leadership holds the line, rank-and-file Republicans are growing uneasy about the political fallout from rising gasoline prices, particularly with the November midterm elections drawing nearer. Senator Mike Rounds of South Dakota said Wednesday he would prefer that the two branches of government work out their constitutional differences through negotiation rather than through congressional votes or court challenges. “We have shared constitutional responsibilities,” Rounds said, calling for direct talks between the White House and Capitol Hill.
War Powers Resolution Faces Long Odds Despite Narrow Margin
The war powers legislation ultimately failed to advance by a narrow margin of 49 to 50, with Senator John Fetterman of Pennsylvania the only Democrat to oppose it. Even if a war powers resolution were to pass the Senate, it would face slim chances in the Republican-controlled House and would almost certainly be vetoed by Trump. The practical effect of Wednesday’s vote was therefore symbolic — a measure of growing Republican discomfort rather than a binding constraint on presidential authority.
Yet the symbolism carries weight. The 49-50 margin was the closest vote yet on Iran war powers, and the addition of Murkowski to the “no” column suggested that further Republican defections are possible if the conflict drags on or if gasoline prices continue to climb.
The Iran war, now entering its third month, has disrupted global oil markets, triggered emergency responses across the energy sector, and tested the limits of presidential war-making power in ways that could reshape the balance of authority between Congress and the White House for years to come.