Seven Republicans broke ranks in the largest GOP defection yet, as Democrats used the vote to pressure vulnerable incumbents ahead of November’s midterms.
Members of the United States House of Representatives have voted for a third time to end the war in Iran, approving a war powers resolution that would curb President Donald Trump’s ability to continue military action without congressional approval.
The vote, held late Tuesday, 15 September, ended 220 to 204, with seven Republicans breaking from the president to join all Democrats.
It is the largest Republican defection on the issue since the conflict began, up from four GOP votes in each of the two earlier successful resolutions, which passed 215-208 in June and 214-208 in July. An earlier attempt in March, before those two, had failed to pass.
None of the three successful resolutions has reached Trump’s desk, where he would almost certainly veto the measure.
Why House Democrats forced another vote
Democratic Representative Seth Moulton of Massachusetts, a former Marine who served in the Iraq War and pushed the latest resolution forward, said Congress needed to reassert its constitutional role.
“Remember when Donald Trump said that this war would last just a few weeks?” he said, adding that it was time for Congress to “actually ask tough questions, as the Constitution directs us to do, rather than be subservient to another warmongering administration.”
The seven Republicans who crossed party lines were Zachary Nunn and Mariannette Miller-Meeks of Iowa, retiring Representative Nancy Mace of South Carolina, Tom Barrett of Michigan, Warren Davidson of Ohio, Brian Fitzpatrick of Pennsylvania, and Thomas Massie of Kentucky.
Nunn, an Air Force veteran facing a competitive re-election race, said he could not support “another open-ended war.” Democrats have acknowledged using the vote as a pressure tactic ahead of November’s midterm elections, targeting Republicans in competitive districts before voters go to the polls.
House Speaker Mike Johnson acknowledged the political weight of the issue, including rising gas prices, but argued the Iran conflict is entering a “new phase” as regional allies step up to help stabilise the situation, rather than backing further congressional restrictions on Trump’s authority.
What happens next in the Senate
It remains unclear whether the Senate will follow the House’s lead. The Senate coming vote comes weeks before the November midterms, in which Democrats are seeking to wrest control of Congress from Republicans.
The Senate had previously approved its own war powers resolution earlier this year, only for Republican senators to reverse course the following day after Trump reportedly berated them during a closed-door lunch.
The White House separately challenged the House’s June resolution, and the Senate has yet to act on the House’s July vote. Senator Thom Tillis of North Carolina, who voted against the earlier resolutions, has said he intends to vote “yes” on the next Senate measure as a pressure tactic of his own.
“It’s time to be clear on the strategic objectives and start measuring results. That’s not something that we’ve had since they started the conflict,” he said.
Background to the conflict
Trump launched the military campaign against Iran in coordination with Israel, with hostilities beginning on 28 February 2026, without seeking congressional authorisation or a formal declaration of war.
He has variously described the conflict as a “skirmish” or “short-term excursion,” and has defended the campaign publicly, saying it has degraded Iran’s military capabilities. Trump had promised, during his 2024 campaign, not to involve the US in new foreign wars if elected to a second term.
