House Republicans on Thursday narrowly blocked a challenge to President Donald Trump’s authority to continue combat operations in Iran, fending off a Democratic-led effort to halt the war even as bipartisan frustration grows over a conflict that has dragged on for weeks without congressional consent.

But even as the GOP thwarted the measure, some in the party indicated that support for the conflict, now nearing its eighth week, was not open-ended and could wane as an initial statutory deadline approaches within weeks for Trump to either withdraw U.S. troops or certify to Congress it is not yet safe for U.S. troops to withdraw.

After the vote, Rep. Brian Mast, R-Fla., the chair of the Foreign Relations Committee, signaled that patience within his party was running thin and that a resolution to halt the military campaign could very well pass in the coming weeks.

The House could “have a different vote count after 60 days,” Mast said, alluding to a May 1 deadline that falls 60 days after Trump formally notified Congress last month of the military operation in Iran.

Asked if the vote would be closer then, Mast predicted that it would. Had just one additional Republican switched positions and voted in favor of the resolution Thursday, it would have advanced.

Instead, the House voted 214-213 against bringing the war powers resolution to the floor, preserving the broad discretion Republicans have afforded to Trump to direct the U.S. military campaign in the Middle East.

But the slim margin signaled continuing unease in Congress as the war proceeds with no clear endgame, and with the approach of the midterm elections in which high gas prices threaten to sour voters on Republicans fighting to keep their majorities.

“Thus far, neither side has indicated what comes next, beyond continued blockage of the Strait of Hormuz,” Rep. Gregory Meeks of New York, the top Democrat on the House Foreign Affairs Committee who led the resolution, said before the vote. “We are standing at the edge of a cliff, and Congress must act before this president pushes us off. Every day we delay, we inch closer to a conflict with no exit ramp.”

Democrats pointed to increased energy costs and uncertainty over the fate of diplomatic talks to end the conflict, insisting that Congress must assert its constitutional authority over an unpopular war that is having deep impacts in their communities.

Many Republicans rejected those arguments and said that limiting the president as he commands thousands of deployed service members in the region would be detrimental to the operation.

“My colleagues, in an ill-advised way, want to say, ‘Remove all U.S. forces,’ in the midst of this ceasefire that we’re in; that’s crazy,” Mast said before the vote.