The biggest impediment to filibuster reform has never been Republicans. Senate rules can be changed without them, and their threats of retaliation are mostly bluster. In reality, the biggest impediment has always been Democrats themselves. Harry Reid needs nearly unanimous consent from his own caucus, and there have always been a handful of Dems who are leery of change. The question is, how big a handful? Greg Sargent summarizes the current state of play:
The Hill reports this morning that senators Dianne Feinstein, Mark Pryor, and Carl Levin are uncomfortable with a simple-majority change. Senators Max Baucus and Jack Reed have yet to be persuaded. Senators John Kerry and Jay Rockefeller say they're undecided but leaning towards a change. Senator-elect Joe Donnelly is uncommitted. Presuming Republicans vote unanimously against any changes, if Harry Reid loses six votes, filibuster reform is toast.
It's unclear what the objections are from these senators. In the case of someone like Dianne Feinstein, it's probably just institutional conservatism. In the case of someone like Mark Pryor, it's probably the fact that he represents a conservative state. In the case of more liberal senators, it may be fear of what Republicans can do if and when they return to the majority.
But any way you slice it, getting 50 Democratic votes is the real challenge here, and if the Hill is right, Reid is having trouble rounding up those votes even for the very modest set of reforms he's proposing. Stay tuned.