US Senate Sees Republican Cross Voting As It Advances Bill Aimed At Ending Iran War

Last Updated:May 20, 2026, 08:01 IST

US Senate advances Iran war powers resolution 50-47, four Republicans back limits on Donald Trump, highlighting GOP divisions as House prepares a similar vote

A rare instance of cross-voting in the US Senate has exposed growing unease within President Donald Trump’s own Republican Party over the ongoing Iran war, as lawmakers advanced a resolution seeking to curb the president’s authority to continue military operations without congressional approval.

The Senate voted 50-47 on Tuesday to advance the war-powers resolution, with four Republicans joining nearly all Democrats in backing the measure. The vote marked the first time either chamber of Congress has advanced legislation aimed at limiting Trump’s military operations against Iran since the conflict began more than 11 weeks ago, according to AFP.

While the resolution still faces significant hurdles — including a likely veto from Trump and resistance in the Republican-controlled House — the procedural vote underscored widening fractures within the Republican ranks over the direction and duration of the conflict.

REPUBLICANS BREAK RANKS

Republican Senators Rand Paul of Kentucky, Susan Collins of Maine, Lisa Murkowski of Alaska and Bill Cassidy of Louisiana crossed party lines to support the measure. Democratic Senator John Fetterman of Pennsylvania was the lone Democrat to vote against it. Three Republicans were absent during the vote.

According to AP, Cassidy’s switch was especially significant because he had previously opposed similar resolutions. His decision came days after he lost a Republican primary contest to a Trump-backed challenger.

“While I support the administration’s efforts to dismantle Iran’s nuclear program, the White House and Pentagon have left Congress in the dark on Operation Epic Fury," Cassidy said on social media, according to AP.

“Until the administration provides clarity, no congressional authorization or extension can be justified."

AP reported that Cassidy returned to Washington “defiant" after his primary defeat and indicated he would carefully reconsider his stance on several Trump administration priorities going forward.

DEMOCRATS SAY “MOMENTUM IS BUILDING"

Democrats argued that the vote reflected growing bipartisan frustration over Trump’s handling of the war and the administration’s reluctance to seek congressional authorization.

“Republicans are starting to crack, and momentum is building to check him," Senate Democratic leader Chuck Schumer said after the vote, according to AP.

“We are not letting up."

Ahead of the vote, Schumer sharply criticised Trump’s approach to the conflict.

“This president is like a toddler playing with a loaded gun," he said, according to AFP.

“If there was ever a time to support our war powers resolution to withdraw troops from hostilities with Iran, it’s now."

Democratic Senator Tim Kaine of Virginia, who sponsored the resolution, said the current ceasefire offered the administration an opportunity to present its case before Congress.

“That’s the perfect time to have a discussion before we start up war again," Kaine said during Senate debate, according to Reuters.

“The president is receiving peace and diplomatic proposals that he is throwing into the trash can without sharing them with us."

CONCERNS OVER LONG-TERM STRATEGY

The Iran conflict began after Trump ordered attacks in late February. Since then, lawmakers from both parties have increasingly questioned whether the administration has a long-term military or diplomatic strategy.

Reuters reported that Democrats and some Republicans have argued the US Constitution gives Congress — not the president — the authority to declare war, and warned Trump may have entered the country into a prolonged conflict without outlining a clear plan.

The resolution invokes the 1973 War Powers Act, legislation passed after the Vietnam War to limit prolonged military campaigns without congressional approval. Under the law, presidents can engage in military action for 60 days before requiring authorization from Congress or seeking a limited extension.

Republican Senator Mike Rounds of South Dakota acknowledged that some Republicans were increasingly concerned about the broader trajectory of the war.

“The War Powers Resolution of 1973 does provide an avenue for that discussion and debate to occur," Rounds said, according to AP.

“But I think a number of our members maybe just feel like it’s time to have the debate."

HOUSE VOTE EXPECTED NEXT

Attention has now shifted to the House of Representatives, where lawmakers are expected to vote on a similar resolution on Wednesday. AP reported that Democrats are optimistic after a previous House war-powers measure narrowly failed in a tied vote last week.

Even if Congress ultimately passes legislation compelling Trump to withdraw from the conflict, the White House has indicated it may argue the War Powers Resolution no longer applies because the administration considers hostilities to have technically ceased under the current ceasefire arrangement.

Still, Tuesday’s vote signaled a politically significant moment for Trump, revealing visible cracks within Republican ranks as concerns mount over the war’s financial cost, military impact and uncertain endgame.

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