Why didn't the Dems block Mukasey?

Glenn Greenwald asks what happened to the Senate's "60-vote requirement"? since Mukasey only mustered 54?

Greg Sargent (Election Central-TPM) answers with "Reid Allowed Vote On Mukasey In Exchange For Military Funding Bill":

According to sources inside and outside the Democratic leadership, Harry Reid allowed a vote on Mukasey because in exchange the Republican leadership agreed to allow a vote on the big Defense Appropriations Bill, which contains $459 billion in military spending but doesn't fund the wars in Iraq and Afghanistan.

Reid had wanted to get this bill passed before the end of this week, and in fact, the defense bill did come up for a vote late last night and was passed after the Mukasey vote.

One key reason Dem leaders wanted this defense approps bill passed, sources tell me, is that they wanted to be able to argue that they had sent a bill to the President funding the military, if not the war itself. The idea was that doing this would allow them to protect themselves in the days ahead when the battle over Iraq funding heats up and Republicans inevitably charge that Dems are refusing to fund the troops.

"This lets us argue, `Hey, we just sent $450 billion to the military," one leadership source tells me.

Howie P.S.: Off topic, Ben Smith supplies the answer (in Eastern Standard Time) to today's burning question for political junkies:

JJ Dinner on CSPAN

If you're interested, they're carrying the premier Iowa event live starting around 8:00 p.m.