The House approved a third war powers resolution aiming to force an end to the conflict with Iran late Tuesday, with a record seven Republicans voting in favor of the effort. 

Reps. Nancy Mace (R-SC), Mariannette Miller-Meeks (R-IA) and Zach Nunn (R-IA) joined Reps. Tom Barrett (R-MI), Warren Davidson (R-OH), Brian Fitzpatrick (R-PA) and Thomas Massie (R-KY), who had previously supported war powers efforts, in voting for the resolution.

Miller-Meeks and Nunn are both facing competitive midterm races in toss-up districts. Nunn in particular has generally been a hawk on Iran. Mace, who is retiring from Congress after losing the South Carolina gubernatorial primary, has previously expressed some criticisms of the war and has proven to be an unpredictable vote on a range of issues.

“Iran must be held accountable for killing Americans, supporting terrorism, threatening the Strait of Hormuz, and pursuing nuclear weapons. Iowa has already paid a devastating price, including two service members killed by an Iranian drone in Kuwait,” Nunn said in a statement. “Congress owes them, their families, and every American in uniform clear objectives and constitutional oversight. With the negotiating window closed, sustained combat operations now require congressional authorization.”

Emphasizing his own service record, Nunn said he “will not support another open-ended war. We can defend Americans, pressure Iran, and pursue peace while ensuring Congress fulfills its constitutional responsibility.”

Miller-Meeks and Nunn’s shifting votes in particular underscore the pressure that some swing-district Republicans are feeling over the war, which polls poorly and has contributed to rising gas prices in the United States.

“The president must end this failed war and appoint real diplomats, not real estate developers, to work multilaterally on a diplomatic solution that opens the Strait and reduces tensions. The American people have made it clear that they do not support this war, and the Constitution does not grant Trump the authority to wage it without the consent of the people and their representatives,” Rep. Greg Meeks (D-NY), the ranking member of the House Foreign Affairs Committee, said in a statement following the vote.