The Senate adjourned for a two-week Thanksgiving recess Thursday without completing work on an annual defense policy bill that members on both sides of the aisle deemed crucial to national security.

Republican senators blocked a procedural motion to end debate on the National Defense Authorization Act, arguing that they had not been given a chance to offer amendments to the bill.

"We used to have a practice -- maybe they'll change it -- of allowing votes on amendments," said a visibly frustrated Sen. John McCain, R-Ariz.

Republicans, still irked that Democrats imposed the "nuclear option" to limit the minority party's use of the filibuster, were in no mood to cooperate with Democrats on the defense bill.

Senate Armed Services Committee Chairman Carl Levin, D-Mich., said he was confident that the bill would be completed somehow.

"We're going to try to get this bill done. We've done it before under even more difficult circumstances, believe it or not. One year we got it done on unanimous consent on the last day of the session," Levin said. "This bill is too important for our troops, for our families, for our national security for me to in any way give up."

Senators on both sides of the aisle, including Levin, had previously warned that the defense bill had to clear the Senate this week, otherwise they risked breaking a 51-year tradition of bipartisan cooperation on the NDAA — even in years they couldn't agree on a federal budget. Now, with only two work weeks left in the legislative session, there is a real risk that the defense bill won't be passed.

The NDAA process has included debates over a variety of military policies, including missile defense, the Navy's biofuel use, Guantanamo detainee policies, troop pay increases and defense budget cuts.

Also left behind by the Senate on Thursday were planned amendment votes on controversial issues, like a proposal from Sen. Kirsten Gillibrand, D-N.Y., to reduce sexual assaults in the military.

Gillibrand said she was confident that her proposal — the Military Justice Improvement Act — would get a vote later, either on the defense policy bill or as a stand-alone bill.

"We hope to get a vote on our [proposal], either up-or-down or as an amendment," Gillibrand told the Washington Examiner.