Washington — The Senate on Tuesday narrowly rejected a war powers resolution on Iran as President Trump touts a framework agreement with Tehran to end the monthslong conflict.

Senators rejected a motion to discharge the resolution out of committee in a 47 to 48 vote. Four Republicans — Sens. Susan Collins of Maine, Bill Cassidy of Louisiana, Lisa Murkowski of Alaska and Rand Paul of Kentucky — joined nearly all Democrats in favor. Sen. John Fetterman of Pennsylvania was the sole Democrat to oppose. 

The vote comes as lawmakers are eager for more information about the terms of a U.S.-Iran deal that remains secret. In 2015, Congress passed the Iran Nuclear Agreement Review Act, which requires that any deal relating to Iran's nuclear program be submitted to Congress for review before any sanctions can be lifted. Senate Majority Leader John Thune, a South Dakota Republican, told reporters earlier Tuesday that he had requested the text of the agreement along with a briefing from the administration. 

The war powers resolution, led by Democratic Sen. Raphael Warnock of Georgia, would direct the president to "remove the United States Armed Forces from hostilities within or against Iran, unless explicitly authorized by a declaration of war or a specific authorization for use of military force."

Speaking on the Senate floor ahead of the vote, Warnock appealed to his colleagues across the aisle: "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?"

GOP support for the war has begun to crack in recent weeks. For the first time last month, the Senate advanced a resolution to limit Mr. Trump's war powers in Iran after seven failed attempts. Senators approved the motion to discharge the resolution from committee in a 50 to 47 vote, with the support of the same four Republicans who supported Warnock's resolution on Tuesday. Three GOP members were absent at the time, tipping the scales in Democrats' favor for the first time since the Iran conflict began.

Senate Minority Leader Chuck Schumer said at a news conference that "we want to make sure all the votes are there before we move the Kaine resolution further."

The New York Democrat said they're trying to get a few more GOP members to vote for the Kaine resolution to move forward.

"It's up to Republicans," Schumer said.

Earlier this month, the House passed a separate resolution to force Mr. Trump to end the war in Iran without congressional authorization, also marking the first successful attempt in the lower chamber to rein in the president as the conflict loses GOP support. The Senate, however, has not taken up the measure. 

The administration has argued that the War Powers Resolution of 1973 — which says the president must remove armed forces from hostilities if Congress has not authorized the war — is unconstitutional. It has also asserted that a statutory 60-day deadline for the president to terminate the use of force, if he does not have consent from Congress, was paused by a ceasefire in early April, though both sides have carried out attacks since then. 

A group of Democratic senators sent a letter to the president earlier this month pressing him on the administration's legal justification that hostilities had "terminated" after the April ceasefire announcement. 

"The United States and Iran, and their associated partners and proxies, have continued to use lethal force in contravention of the ceasefire, which also constitute hostilities. Finally, U.S. forces remain postured for, and you have regularly threatened, the swift return of major combat operations," said the letter, which was led by Democratic Sen. Adam Schiff of California. 

The letter also said that the 60-day clock "does not have a pause button" and urged the president to publicly release the "legal theory underlying your interpretation to the contrary in a timely manner."