NBC's Ken Strickland reports that a vote on the Defense Authorization Bill, which contains the "Don't ask, Don't Tell" repeal, failed 56-43. Democrats needed 60 votes to overcome a filibuster. This was a "motion to proceed" vote that would have moved the bill forward to be debated.
Republican moderates Susan Collins (ME), Olympia Snowe (ME), and Scott Brown (MA) all voted "no" with rest of GOP.
Other vote notes:
Democrats voting no: Blanche Lincoln (AR), Mark Pryor (AR), and Harry Reid. (Reid changed his vote to "no" for procedural reasons to be able to call for another vote later.)
Senators not voting: Lisa Murkowski (AK), who is focused on a write-in bid for reelection in Alaska.