The Senate shut down for the holidays without acting on nominations for four key Pentagon posts and the top health care job at the Veterans Affairs Department.

Defense Department posts left in limbo by the Senate on Thursday include Clifford Stanley's nomination to be undersecretary of defense for personnel and readiness, and Erin Conaton's nomination to be undersecretary of the Air Force.

Stanley is a retired Marine Corps major general who, if confirmed, will be the Obama administration's point man on revising the military's ban on open service by homosexuals. Conaton has been staff director of the House Armed Services Committee, closely allied with its chairman, Rep. Ike Skelton, D-Mo., a leading voice on national security policy for House Democrats.

Also left on the executive calendar of pending nominations that were approved by a committee, but not by the full Senate, is Frank Kendall III to become principal deputy undersecretary of defense for acquisition, technology and logistics, and Terry Yonkers to become an assistant Air Force secretary.

The four defense nominees were approved Dec. 2 by the Senate Armed Services Committee.

Holds on defense executives have been common this year because senators have been freezing nominations as a ploy to get the Obama administration to provide more details about the fate of detainees being held at the military prison on Naval Base Guantanamo Bay, Cuba. It was not immediately clear which senator or senators were responsible for delay, as nobody has stepped forward to say they were using their senatorial rights to prevent a vote.

The nomination of Dr. Robert Petzel to become VA undersecretary for health also did not come to a final vote before senators left town. Petzel, a current VA health care executive, was approved for the new post by the Senate Veterans' Affairs Committee on Dec. 16.

Senators return to work the week of Jan. 20, which is the soonest a vote could come on the nominations.