Ezra Klein has two helpful posts up this morning about the process going forward with the health care bill. I certainly agree with him (and against Maddow) that this isn't about will power and fear, and I appreciate his timely reminder that the president has consistently pointed to conference, and not the initial bill out of committee, is that really matters.
I think that he vastly overestimates the pressure that can be brought on individual Senators at this point, however, when he suggests "identifying a lot of viable primary challengers" to Senators who won't support a liberal bill. As I've said, this is a very tricky business. You don't want to end up with the liberal equivalent of the Club for Growth. It's not quite true that there couldn't be a more liberal Senator in North Dakota than Kent Conrad -- if pressed in a primary, Conrad could probably throw a few more votes to liberals and still survive a general election -- but it is probably true that it's very unlikely that someone could beat him from the left in a primary and then go on to win the general election. Virtually all of the key moderate Democrats come from similar states: Nebraska, Missouri, Arkansas, Louisiana. Montana. You just aren't going to have much success trying to get Democratic Senators from those states to cast votes clearly identified as liberal.