The Senate voted Tuesday against a resolution that aimed to prevent President Donald Trump from authorizing additional U.S. military strikes on Iran, dealing a blow to Democrats’ efforts to end the ongoing conflict. The vote took place days after the United States and Iran reached a limited agreement intended to halt months of hostilities and pave the way for broader negotiations.

The resolution, introduced by Sen. Raphael G. Warnock (D-Georgia), failed narrowly on a procedural vote, 48-47. Four Republican senators—Susan Collins (Maine), Bill Cassidy (Louisiana), Lisa Murkowski (Alaska), and Rand Paul (Kentucky)—joined Democrats in supporting the measure. However, one Democrat, Sen. John Fetterman (Pennsylvania), opposed the resolution, leaving Democrats just short of the votes needed for passage.

This outcome marks a setback for Democratic lawmakers who have sought to compel Trump to end the conflict through congressional action, despite the president’s assertions that recent hostilities have ceased following an April ceasefire. Under the 1973 War Powers Resolution, presidents must withdraw U.S. forces from conflicts not authorized by Congress within 60 days; Trump argued the ceasefire rendered continued military engagement unnecessary to end by May 1.

Senate Minority Leader Charles E. Schumer (D-New York) described the vote as a gauge of Republican support for similar measures, emphasizing Democrats’ ongoing efforts to persuade more GOP senators. “We’re one short right now,” Schumer said, referencing the minimum number of Republican defections required to advance Sen. Tim Kaine’s (D-Virginia) related resolution, which the Senate previously voted to advance in May.

Five senators—Bernie Sanders (I-Vermont), Josh Hawley (R-Missouri), Mitch McConnell (R-Kentucky), Cory Booker (D-New Jersey), and Michael Bennet (D-Colorado)—were absent from Tuesday’s vote; their absences did not decisively influence the outcome. Had they voted consistently with prior positions, the resolution would have resulted in a 50-50 tie.

The Senate still has the option to revisit Kaine’s war powers resolution, but passing such a measure would require multiple votes and face a probable presidential veto. Overriding a veto would take a two-thirds majority in both chambers, a threshold no war powers resolution has ever met.

Despite the vote, Democrats signaled their intention to continue pressing for congressional limits on Trump’s military authority, citing concerns that the president could resume strikes against Iran even as the two countries prepare to sign a memorandum of understanding in Switzerland on Friday. Warnock highlighted the unresolved risk, stating on the Senate floor that while the conflict might be winding down, “the question before this body is: Will this president do this again? I think the answer is yes.”

Republican leaders largely endorsed Trump’s handling of the situation but expressed cautious optimism about the forthcoming agreement, which has not been fully disclosed to them. Senate Majority Leader John Thune (R-South Dakota) said he awaited more information before fully endorsing the administration’s approach but affirmed his confidence in the president’s direction.

Some Republicans who voted for the resolution, such as Cassidy, did so after facing politically challenging primary battles influenced by Trump’s endorsements of their opponents. Others, like Sen. John Cornyn (R-Texas), who lost a recent primary with Trump’s backing elsewhere, resisted efforts to constrain Trump’s military options. Cornyn criticized the resolution as an attempt to “tie the president’s hands” in dealings with Iran.

Kaine, who has led Democrats’ legislative strategy on the issue, indicated he is waiting to secure sufficient Republican support before bringing his resolution to the floor for a final vote. “I don’t have a fifth, sixth or seventh Republican vote yet,” Kaine said, but expressed optimism that additional GOP senators might join the effort soon.