The Senate on Tuesday narrowly turned back the latest attempt to force President Trump to withdraw U.S. forces from the conflict with Iran, falling short on a 47-48 vote days before Washington and Tehran are expected to sign a preliminary agreement to end the war.

The measure, a motion to discharge a war powers resolution from the Senate Foreign Relations Committee, was sponsored by Sen. Raphael Warnock of Georgia. It marked the ninth attempt by Democrats to assert a stronger congressional role over the war since the United States and Israel began air attacks on Iran in February.

Four Republicans, Bill Cassidy of Louisiana, Susan Collins of Maine, Lisa Murkowski of Alaska, and Rand Paul of Kentucky, crossed over to support it, the same four who backed a similar measure last month. Sen. John Fetterman of Pennsylvania was again the only Democrat to vote against.

The math behind the margin

Five senators missed the vote: Democrats Michael Bennet of Colorado and Cory Booker of New Jersey, independent Bernie Sanders of Vermont, and Republicans Josh Hawley of Missouri and Mitch McConnell of Kentucky. Their absences did not change the outcome. Had all five voted as they have on past resolutions, the tally would have been a 50-50 tie, which Vice President JD Vance, a central broker in the Iran talks, would have broken in the Republicans' favor.

That arithmetic left Democrats one vote short. To pass any such resolution, they need to flip a fifth Republican. A separate resolution introduced by Sen. Tim Kaine of Virginia cleared a procedural hurdle last month on a 50-47 vote, and Democrats have kept it alive rather than forcing a final tally they expect to lose. "We're trying to get a few more Republicans to vote for the Kaine resolution so we can move forward," Minority Leader Chuck Schumer said. "We're one short right now."

The roll call produced a moment of suspense. Sen. Thom Tillis of North Carolina, who has broken with Trump on several issues this year, signaled beforehand that he was weighing a yes vote, questioning aloud whether the country was in a ceasefire, a new agreement, or something else, and suggesting that lingering uncertainty might warrant a formal authorization for the use of military force. He walked onto the floor late in the roll call and pointed his finger down to register a no.

Two readings of the same moment

Warnock framed the vote as a test of whether Congress would reassert itself. He argued that the truce restored the prior state of affairs at best and pressed colleagues to act. "After 109 days of a failed war and now a fragile, temporary but welcome truce, will my Republican colleagues choose today to finally stand up to this president?" he asked. Pressed on whether Trump might resume strikes, he said he believed the answer was yes.

Kaine made a similar case, calling the lull the ideal moment to specify that the war should not resume without the congressional consultation he said should have preceded it. After the vote, he said the administration was working "harder and harder and harder" to keep additional senators from joining, and that while he did not yet have a fifth Republican, he thought one might come. Sen. Chris Murphy of Connecticut questioned the substance of the emerging deal, saying that what little was known suggested it amounted to a payment to Iran to reopen the Strait of Hormuz, eroding the leverage needed to press Tehran on its nuclear program.

Republican leaders urged patience. Majority Leader John Thune said he wanted more detail but trusted that Trump and his team were moving in the right direction. Jim Risch of Idaho, who chairs the Foreign Relations Committee, dismissed the measure as a counterproductive maneuver, arguing that voting to end the war while the president was overseas would give comfort to an adversary and could jeopardize the talks. He maintained that U.S. forces had not been engaged in hostilities for some time, despite continued deployments and intermittent strikes since the April ceasefire.

The primary calendar cut in different directions. Cassidy backed the resolution after losing a primary in which Trump had endorsed a challenger. Sen. John Cornyn of Texas, who also lost a primary last month after a Trump endorsement of his opponent, declined to use the vote to defy the president. "I don't want to tie his hands when it comes to dealing with the Iranian regime," he said.

The legal backdrop

Democrats have leaned on the War Powers Resolution of 1973, which requires a president to pull U.S. forces from an unauthorized conflict within 60 days. Trump reached that deadline on May 1 but argued it did not apply, contending that hostilities had ended when a ceasefire took hold in April.

The path to actually constraining the president remains steep. Both chambers would have to pass Kaine's resolution, after which Trump would almost certainly veto it, requiring a two-thirds override in each chamber. No war powers resolution has ever survived a presidential veto. Separately, any agreement touching Iran's nuclear program would have to be submitted to Congress under a 2015 law that allows lawmakers to try to block it through a disapproval resolution.

A deal hanging over the debate

The vote unfolded against the backdrop of a framework the White House and Tehran announced over the weekend, with officials from both sides expected to sign a memorandum of understanding in Switzerland on Friday, opening a 60-day ceasefire and a window for broader negotiations. Many lawmakers in both parties complained that they had not been shown the text, and Democrats said they had been kept in the dark.

Momentum has built slowly. The House passed its own resolution this month, 215-208, with four Republicans joining Democrats, a vote Trump called unpatriotic. Democrats have signaled they will keep forcing the issue, warning that the president could restart the war if the coming talks falter. Schumer said the caucus would wait until the votes were lined up before bringing Kaine's measure back to the floor, leaving the standoff to continue even as the ink dries on the agreement in Geneva.