A measure to limit President Trump’s authority to wage war with Iran could come up for a vote in the Senate as soon as Tuesday. The sponsor of the Senate version, Virginia Democrat Tim Kaine, already has two GOP senators on board, Mike Lee of Utah and Rand Paul of Kentucky.

But Kaine needs two more Republicans to get the 51 vote simple majority needed for passage, and he’s hoping that Susan Collins of Maine and Jerry Moran of Kansas, who voted in the past for an amendment limiting funding for military action, will push the resolution over the top.