The Senate has not passed its version of the National Defense Authorization Act — yet — but the main players in an NDAA conference aren’t waiting.

The chairmen and ranking members of the Senate and House Armed Services committees — House Chairman Howard “Buck” McKeon, R-Calif., House ranking member Adam Smith, D-Wash., Senate Chairman Carl Levin, D-Mich., and Senate ranking member James M. Inhofe, R-Okla. — met Monday to discuss how they could conference the defense authorization act in a nearly impossible timeline.

The meeting started at noon and lasted, according to McKeon, until “2:30, 3:00, 3:30 — somewhere in there.”

For that part of the meeting, it was only McKeon, Levin and Inhofe — Smith was still on his way back to the Capitol. But all four met again around 4:30 p.m. to bring Smith up to speed.

At about 5:15 p.m. on Monday, Levin was spotted coming off the Senate subway to the Russell Building carrying a large three-ring binder. Conspicuously, the binder had a sheet of paper slipped into the plastic cover on the outside that read: “Point Pages for Big 4 Meeting.”

None of the participants nor their staffers would say as much, but it appears that the “Big 4” are working out the differences in the defense bills before the Senate passes its version of the authorization measure.

According to aides, the “Big 4” agreed not to discuss the meeting with the press, so details were scant.

“We’re just trying to help move the process along,” McKeon told CQ Roll Call on Tuesday morning, restraining himself from saying more.

The communications director for the House Armed Services Committee, Claude Chafin, told CQ Roll Call that he would “never presume to add to what the chairman said.”

The communications director for Democrats on the House Armed Services Committee, Michael Amato, also said he “can’t get into specifics.”

“Conversations continue to happen on a variety of issues on all levels as we work towards getting a bill to the president,” Amato told CQ Roll Call.

Even with less than two legislative weeks left in this year’s session, hope is running high for the defense authorization measure.

McKeon told CQ Roll Call that he was “very confident” the defense bill would be signed into law for a 52nd consecutive year.