The Senate on Wednesday rejected the seventh attempt by Democrats to force an end to American involvement in the war on Iran, even as the ranks of Republicans opposed to Donald Trump’s strategy grew.

The war powers resolution proposed by Jeff Merkley, a Democratic senator of Oregon, failed in a 49-50 vote. All Democrats with the exception of John Fetterman of Pennsylvania supported its advancement.

Since the conflict began in February, Democrats have repeatedly offered such resolutions, without success. But for the first time on Wednesday, Alaska’s Lisa Murkowski voted in favor, joining fellow Republicans Rand Paul of Kentucky and Susan Collins of Maine. All other Republicans in attendance voted against it.

A spokesperson for Murkowski did not immediately respond to a request for comment. The senator is one of the few in the chamber to occasionally break with Trump during his second term, and last month said that passage of a war powers resolution “would have halted operations that were already underway without any framework for what comes next, and that’s just something I can’t support”.

Congress did not formally authorize the US campaign against Iran and Murkowski has said she is working with other lawmakers on an Authorization for the Use of Military Force (AUMF), which would be similar to what Congress approved following the 9/11 attacks and ahead of the 2003 US invasion of Iraq. That measure has not been released yet.

Chuck Schumer, Senate’s Democratic minority leader, criticized Republicans for enabling the conflict, noting that several have said they would want Congress to authorize any hostilities that continue beyond the 60-day mark, a deadline which has since passed.

“We gave Republicans yet another chance to vote with us, honor their words, and hold the president accountable. But they continue to bow a knee to Trump,” Schumer said.

The Trump administration has argued that because the US and Iran have agreed to a ceasefire, the 60-day deadline for Congress to vote on continuing the conflict, which is spelled out in the 1973 War Powers Act, no longer applies.