The House GOP’s budget resolution is hanging in the balance as a handful of hardliners withhold support for the measure, setting the stage for a high-stakes committee vote on Thursday.

At least six Republicans on the House Budget Committee remained undecided Wednesday afternoon on whether they will support the budget resolution when the panel considers it on Thursday, a number far larger than the two GOP lawmakers the conference can afford to lose and still clear the measure, assuming all Democrats vote “no.”

Hardline conservatives and some other Republicans are pushing for changes to the measure and commitments on spending cuts, a dynamic that is threatening the path forward for the resolution.

“Tomorrow will be a big day,” Rep. Ralph Norman (R-S.C.), one of the Budget Committee holdouts, told reporters. “If it doesn’t go, that puts us back at ground zero.”

Some Budget Committee members, to be sure, were optimistic that the budget resolution would ultimately make it out of the panel on Thursday. But the last-minute negotiating could throw a wrench into the process, forcing Republican leaders into the balancing act of placating hardline conservatives while protecting vulnerable moderates.

“We are having some last-minute conversations,” Rep. Jay Obernolte (R-Calif.) said. “There were a few of us that, you know it’s very complicated, there are a lot of dials and we just want to make sure we get it right.”

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Asked if he was confident the budget resolution would clear the panel on Thursday, the California Republican responded: “I do.”