In Bipartisan Bid to Restrain Trump, Senate Passes Iran War Powers Resolution

“They were in the process of telling us that we need to be good little boys and girls and not debate this in public,” Mr. Lee said then, emerging red-faced from the briefing. “I find that absolutely insane. It’s un-American, it’s unconstitutional and it’s wrong.”

They were joined on Thursday by six other Republicans in supporting the effort to curtail Mr. Trump’s war powers: Senators Lamar Alexander of Tennessee, Bill Cassidy of Louisiana, Susan Collins of Maine, Jerry Moran of Kansas, Lisa Murkowski of Alaska and Todd Young of Indiana.

The vote was the latest in a series of bids by Congress over the past year to rein in Mr. Trump’s war powers. Last year, Congress cleared a bipartisan measure invoking the War Powers Act that would have cut off American military support for the Saudi-led campaign in Yemen’s civil war, and a separate measure seeking to curtail the president’s war-making powers in Iran ping-ponged between the two chambers, passing the House but not the Senate.

Despite a recognition in both parties that much of the American public is weary of perpetual military conflict, the measures drew only modest support from Republicans, each time falling well short of the two-thirds majority vote necessary to override a veto.

Senator Richard J. Durbin of Illinois, the No. 2 Democrat in the Senate, said that he had voted multiple times to send troops to war — first as a member of the House and then later in the Senate. He described them as “the toughest votes” he ever had to cast, “knowing that in the best of circumstances, that Americans will die.”

“Before you make that decision, you have to think long and hard, and many members of Congress would like to race away from that,” he said. He described the rationale adopted by many lawmakers as: “I’d just rather blame the president if it turns out bad.”

Supporters of the resolution approved Thursday saw a glimmer of hope in the final vote tally. In July, the Senate rejected a similar measure to curtail the president’s war powers related to Iran, with only four Republican senators defecting to support it. Twice as many supported the resolution on Thursday.