According to The Hill, as many as 10 Republican senators may back Sen. Tim Kaine's resolution that would limit Trump's ability to take military action against Iran without Congressional approval after the drone strike that killed Qassem Soleimani:
Sen. Tim Kaine (D-Va.) is circulating a bipartisan resolution that would direct Trump to remove U.S. forces from any hostilities against Iran within 30 days of its enactment.
GOP Sens. Mike Lee (Utah) and Rand Paul (Ky.) have already voiced their support for the measure, and Kaine says about eight more Republicans, including Sens. Susan Collins (Maine), Lisa Murkowski (Alaska), Todd Young (Ind.) and Mitt Romney (Utah), are reviewing it.
“Probably about 10,” Kaine said when asked about the number of Republicans who could vote to rein in Trump’s powers. “There’s good discussion going on.”
Lee said several Republicans are carefully weighing whether to back the measure, adding that it “would not be unreasonable to say that there might be a group of 10 who should be considered potential candidates to vote for it.”
Lee also called it a “completely noncontroversial measure” that restates the Constitution’s declaration that Congress shall have sole power to declare war.
