Why does John McCain hate our troops and immigrant children? He succeeded in his filibuster of the defense authorization, which includes a repeal of Don't Ask Don't Tell. This first cloture vote (as David calls it, the vote "to decide whether or not to end debate on the question of whether or not to begin debate on the the defense bill") failed.
To the sound of DNC money being flushed down the toilet, Blanche Lincoln voted with Republicans, as did her Arkansas colleague Mark Pryor. The final vote was 56-43, with Reid also voting no so that he can bring the bill back up. Lisa Murkowski did not vote.
For all of Lady Gaga's lobbying efforts, Olympia Snowe and Susan Collins said that they are deeply committed to ending Don't Ask Don't Tell, but that that mean Harry Reid won't let Republicans have an open amendment process, and so they just couldn't allow debate. Which is kind of, you know, a lie. Reid has actually said he'd work out an agreement with them to determine which and how many Republican amendments would be allowed once they got past this vote to the actual bill.
Here's Collins and Levin on that point.
And of course, Susan Collins and McCain both had ample opportunity to offer amendments when the bill was being considered in the Armed Services Committee. Their arguments are specious and wholly politically based. Passing DREAM and DADT would be far too popular for the Democrats leading into November, and there's no way Republicans--including Collins and Snowe--are going to let that happen. So this fight is being pushed off to the lame duck session.