The Senate voted on Tuesday to advance a war powers resolution aimed at forcing Donald Trump to end the war in Iran unless he receives congressional authorization to continue it.

Tuesday’s 50-47 vote marks the first time the chamber has advanced the bill, the eighth attempt at doing so since the conflict began in February.

Four Republicans joined all but one of the Senate’s Democrats in voting to pass the bill.

This time, Senator Bill Cassidy, fresh from a primary loss in Louisiana in a race where Trump endorsed his opponent, voted to take up the measure.

Lisa Murkowski of Alaska, Rand Paul of Kentucky and Susan Collins of Maine also voted to advance the bill, as they did in previous votes. John Fetterman of Pennsylvania was the sole Democrat to vote against it, while three Republicans did not vote.

Tuesday’s vote marks just the first step toward full passage of the resolution, which Trump will almost certainly veto even if it does pass in both the Senate and the House.

Still, Democrats see the resolution’s advancement as a way to force Republicans to take a stance on Trump’s unpopular war.

“The Senate should use this moment to do what we should have done before the war started – discuss the rationale, strategy, end state, and costs to American taxpayers and our economy,” said the bill’s sponsor, Virginia senator Tim Kaine, in a statement ahead of the vote.

More details soon …