The Senate Armed Services Committee is scheduled to vote on Chuck Hagel’s nomination for defense secretary Tuesday, after much delay.

Some Republicans on the committee are threatening a walkout, but John McCain of Arizona isn't one of them, even though he sparred with Hagel during his hearing, NBC reports.

“I will not participate in any walkout of tomorrow’s committee vote – an action that would be disrespectful to Chairman [Carl] Levin and at odds with the best traditions of the Senate Armed Services Committee," said McCain, who previously served as ranking member of the committee.

But the top Republican on the committee, James Inhofe of Oklahoma, threatened Monday to hold up the nomination if the committee supports him on Tuesday, vowing to force Democrats to come up with 60 votes to confirm him on the Senate floor.

A spokeswoman for Inhofe confirmed to Politico that he wanted to drag out the confirmation process for the former Republican senator from Nebraska.

McCain and Hagel, who both served in Vietnam, were Senate allies until Hagel split with McCain over the “surge” in Iraq, which McCain advocated. They argued over the surge when Hagel appeared before the committee. Nevertheless, McCain, who says he's leaning against Hagel, has come to his defense, arguing against the outright blockage of the nomination.

Days after Minority Leader Mitch McConnell, R-Ky., left open the possibility of filibustering Hagel's nomination, McCain came out against that.

Then, after Inhofe and Sen. Lindsey Graham R-S.C., said they would try to block Hagel, McCain said that was going too far.

For Hagel's part, NBC talked to Chuck Hagel’s brother Tom, who says Chuck Hagel will not withdraw. In fact, he’s going to “fight harder.” Tom Hagel says the only way he’d withdraw is if the White House wanted him to, and the White House is sticking by him.

Majority Leader Harry Reid, D-Nev., said he would hold a full Senate vote on Hagel either Wednesday or Thursday, reports NBC.

“I would expect a party-line vote out of committee, and for the next big fight to happen when Hagel’s vote comes to the Senate floor,” one GOP aide told Politico.

Democrats, who control the Senate, have a 14-12 majority on the Armed Services Committee. So far, only two Republicans — Mike Johanns of Nebraska and Thad Cochran of Mississippi — are supporting Hagel. Neither serves on the committee.