Members of the hard-line conservative House Freedom Caucus are calling on Republican leaders to delay passage of the annual defense authorization bill until after the new year if its demands, like repealing the military’s COVID-19 vaccine mandate, are not met.

In January, a new Congress may include GOP majorities in either the House or Senate that can “rework” the legislation, the group said.

“Congressional Republicans still have the opportunity to stand in defense of our Nation’s military – if we stand united,” the group wrote in a letter to House Minority Leader Kevin McCarthy (R-Calif.) and Senate Minority Leader Mitch McConnell (R-Ky.) on Tuesday.

“Just as they did in July, Democrats will need Republican votes to pass the NDAA, and the House Freedom Caucus urges all Republicans to hold the line to force Democrats to reverse the policies of President Biden undermining our Nation’s military and its combat readiness, starting with the vaccine mandate,” the letter said.

The Senate started debate on its National Defense Authorization Act (NDAA) on Tuesday, and a final vote is expected after the midterm elections. It would then be reconciled in conference with the House version of the NDAA, which passed in June in a 329-101 vote, with 39 Democrats and 62 Republicans voting against the legislation. 

The Freedom Caucus opposed that bill over similar concerns about the vaccine mandate and what it called the “prioritization of ‘diversity’ and ‘inclusion’ over combat readiness.”

Now, the group is also calling for the establishment of a special inspector general to scrutinize U.S. involvement in Ukraine as part of a list of four core demands for the NDAA.

“Republicans must demand that the NDAA: (1) fully repeals the vaccine mandate and allows service members involuntarily discharged to be reinstated without penalty; (2) ends the contamination of our military by radical Leftist ‘woke’ ideologies and the prioritization of politics over combat readiness; (3) halts wasteful spending on ‘Green New Deal’ pet climate projects; and (4) establishes a Special Inspector General on U.S. involvement in Ukraine,” the letter said.

If those are not met, the Freedom Caucus said, Republicans should delay passage until after the start of the next Congress, when the group hopes to have “a new Republican Majority to comprehensively rework the NDAA to serve America’s service members instead of Leftist political agendas.”

Election analysts widely believe that Republicans are favored to win back the House and that control of the Senate is a toss-up.