The Senate narrowly advanced an Iran war powers resolution Tuesday by a vote of 50-47 -- marking the first time the Senate has approved moving forward with this resolution after seven previously failed votes.
Republican Sen. Bill Cassidy, who lost his primary in Louisiana over the weekend after President Donald Trump endorsed his opponent, voted yes to advance the resolution for the first time. He has not yet issued a statement explaining his change in position on the measure.
His GOP colleagues Sens. Rand Paul, Susan Collins, and Lisa Murkowski also voted for the resolution, along with the majority of Democrats. There were multiple GOP absences.
As in past votes, Democratic Sen. John Fetterman was the only Democrat to vote against the resolution.
The resolution "directs the President to remove U.S. Armed Forces from hostilities within or against Iran unless a declaration of war or authorization to use military force for such purpose has been enacted."
The resolution only needed a simple majority in the procedural vote to advance. The Senate would need to vote again to advance the bill. Right now, if no other member changes their votes and there is full GOP attendance, the measure would still ultimately fail. Though it's a breakthrough moment for Democrats who have for months been bringing war powers resolutions to the floor.
"It sort of feels like the momentum is slowly, not fast enough for me, but moving our way, and that's really positive," Sen. Tim Kaine, who has been leading the Democratic effort on war powers, told reporters after the vote.
-ABC News' Allison Pecorin and Lalee Ibssa