The Louisiana senator, who lost his primary over the weekend, voted in support of the war powers resolution for the first time. It advanced 50-47, with a final passage vote yet to come.

The Senate has advanced legislation that seeks to force President Donald Trump to withdraw from the Iran war.

The war with Iran has now blown past the 60-day requirement under the War Powers Act for the president to seek the authorization of Congress.

The bill had previously been shot down with a lack of Republican support, but Sen. Bill Cassidy's defection could be crucial.