The House on Wednesday voted to direct President Trump to withdraw U.S. forces from Iran or win approval from Congress to continue the war, after four Republicans sided with Democrats in a striking sign of growing opposition to a military campaign now in its fourth month.
Adoption of the resolution was a remarkable rebuke to Mr. Trump and his handling of the war, after he has repeatedly dismissed any effort by Congress to curb his power and as the G.O.P. has largely ceded its prerogatives to do so, deferring to him time and again. Republicans had abruptly postponed the vote two weeks ago, recognizing that they did not have sufficient votes to defeat the measure and wanting to spare themselves and the president the affront.
But they made no headway over the ensuing days in winning converts, as the conflict has dragged on and Mr. Trump has made little progress toward ending it. And G.O.P. leaders were unable to delay the vote any longer because Democrats had invoked the War Powers Resolution, which requires consideration of such measures within a limited period of time.
The move was also the latest reflection of divisions between Republicans in Congress and the president on a range of issues as their interests diverge in the run-up to the midterm congressional elections. It came after Senate Republicans have in recent days forced Mr. Trump to abandon his request for $1 billion in security funding for his ballroom project and a plan that the Justice Department announced to create a federal fund to pay claimants who accuse the government of having victimized them.
The vote was 215 to 208 to adopt the war powers resolution, sending it to the Senate. Even if it were to pass both chambers, the ability of lawmakers to force a president to withdraw troops remains a contested legal question, and Mr. Trump and his senior aides have dismissed any effort by Congress to limit his war powers as unconstitutional.
But the vote in the House, and a similar one in the Senate last month when a handful of G.O.P. defectors broke from the president and opposed the war, indicate an increasing willingness by some members of the president’s party to pressure him to end a conflict that a majority of Americans say is not worth the costs.
Republican Representatives Tom Barrett of Michigan, Brian Fitzpatrick of Pennsylvania, Warren Davidson of Ohio and Thomas Massie of Kentucky crossed party lines to vote with Democrats in favor of the resolution. Representative Jared Golden, Democrat of Maine, who had previously opposed similar measures, switched his position to support it.
Though the few defections were notable, almost every Republican voted against the resolution. Most of them have accepted the Trump administration’s claim that Iran posed an imminent threat to the United States, the legal threshold under the War Powers Resolution of 1973 for the president to order attacks on a foreign adversary without the permission of Congress.
Many have dismissed Democrats’ war powers measures, which call for the removal of most U.S. forces from hostilities in Iran, as politically motivated attacks on the president that would leave American interests unprotected.
Democrats contended that members of both parties must protect the role of Congress to determine when and how the country undertakes prolonged combat operations overseas.
The House’s vote was only the first step in a complicated and likely uphill path for the resolution. It now heads to the Senate, which under the war powers law must take it up within roughly two and a half weeks. It does not need a presidential signature, but even if Congress were to clear the measure, its legal force would remain uncertain.
While Congress has historically deployed concurrent resolutions to express its position on an issue without requiring presidential approval, the Supreme Court held in 1983 that in order for congressional actions to have binding legal effect, they must go through the standard legislative process, including being presented to the president to be signed into law.
That means any attempt to make the directive to withdraw U.S. forces in Iran legally enforceable would almost certainly require Mr. Trump’s signature, or have two-thirds of both chambers vote to override a veto.
The Senate is pursuing a parallel track. Last month, four Republicans and all but one Democrat voted to advance a separate war powers resolution toward a full floor vote, but that effort faces procedural hurdles of its own.
But while the practical odds of either measure forcing an end to the war remain slim, the action in both chambers amounted to a notable reproach of the president’s handling of the conflict.
Democrats have argued that even symbolic congressional action could pressure Mr. Trump to alter course by signaling growing bipartisan discomfort with a longer war.
