House Republicans on Tuesday advanced their bill to avert an end-of-the-week government shutdown, teeing up a final vote on the legislation later in the day.

The chamber voted 216-214 to adopt a rule which governs debate on legislation for Speaker Mike Johnson’s (R-La.) continuing resolution. The measure would keep the government funded through Sept. 30, the end of the fiscal year, boost defense funding and impose cuts for nondefense programs.

Rep. Thomas Massie (R-Ky.) was the lone Republican to cross the aisle and vote against the rule.

The successful vote allows the House to debate the measure and hold a final vote, which is scheduled for 4 p.m. EDT.

It remains unclear, however, whether the bill will have enough support to pass. Massie has said he will vote against the legislation, and a number of other Republicans remained undecided as of Tuesday morning even after hearing a pitch from Vice President Vance including Reps. Tim Burchett (Tenn.), Kat Cammack (Fla.), Beth Van Duyne (Texas) and Rich McCormick (Ga.).

“I’d like verification that in the future that we’re going to reduce the spending at the Pentagon,” Burchett said Tuesday morning when asked about his indecisiveness.

Reps. Brian Fitzpatrick (R-Pa.) and Cory Mills (R-Fla.) previously said they were undecided, and Rep. Tony Gonzales (R-Texas) has told reporters he will make a “game-time decision” on whether to support the measure.

Democrats, meanwhile, are expected to oppose the legislation in large numbers. House Minority Leader Hakeem Jeffries (D-N.Y.), House Minority Whip Katherine Clark (D-Mass.) and House Democratic Caucus Chair Pete Aguilar (D-Calif.) all said they will vote against the measure, raising concerns about cuts in the legislation.

“House Democrats are voting no,” Aguilar told reporters Tuesday, adding “we’re working to make sure that every Democrat votes ‘no’ and is here and present on the floor.”

Those dynamics are posing a difficult equation for Johnson. If all Democrats vote “no” and there is full attendance in the chamber, the Speaker can afford to lose only one GOP vote and still clear the measure.

Potential Democratic absences, however, could alter that margin, giving Johnson more breathing room. Rep. Raúl Grijalva (D-Ariz.), for example, has been out of Washington for weeks following a cancer diagnosis. Grijalva missed the rule vote. It remains unclear whether he will be in the Capitol for Tuesday’s final vote.

House Budget Committee Chair Jodey Arrington (R-Texas) also missed the vote, though it remains unclear if he will be absent for the final vote.

Any Democratic support for the legislation would also help Johnson get the measure over the finish line. Moderate Democratic Reps. Jared Golden (Maine) and Marie Gluesenkamp Perez (Wash.) would not say how they plan to vote on the measure when asked by The Hill Monday evening.

“Have a good night,” Perez said when asked if she would vote for the stopgap.

Johnson, for his part, was optimistic he would have the votes to clear the legislation Tuesday morning.

“We will have votes,” Johnson said during a press conference. “We’re going to pass the CR. We could do it on our own. But what I’m saying is, Democrats ought to do the responsible thing, follow their own advice in every previous scenario and keep the government open.”

Even if the bill does clear the House, its fate in the Senate remains unclear. With 60 votes needed to break a filibuster and Sen. Rand Paul (R-Ky.) opposed to the measure, Republican leaders will need at least eight Democratic votes to clear the legislation. While some key Democrats have cast doubt on the measure, a handful of others are keeping their cards close to the vest.

Updated at 2:53 p.m. EDT