I’ve seen lots of worrying lately about what a large Senate Democratic caucus would mean for party discipline, and the general consensus seems to be that Democrats will never “stay in line.” It’s certainly the case that Democrats have generaly had a harder time keeping their caucus whipped into line than the Republicans, and it’s definitely hard conventional wisdom now, but I think we may be overstating the case somewhat now. Here’s Digby:

This reminds me of something that’s been driving me nuts for the past few days. The gasbags are chattering excitedly about the potential filibuster-proof Democratic senate majority. On what planet does anyone think that’s actually going to be operative? It wouldn’t happen with people like Ben Nelson or Mary Landrieu, much less Holy Joe. In fact, this fantasy would put Lieberman right back where he was in the last congress — the deciding vote. Oy vey. They’d be better off just sticking with 59 votes than let that jackass run his game anymore.

I’m just not sure that’s likely to be the case. I think the problem is that we’re operating under the assumption that it takes 60 votes to pass a major package, because it has generally taken 60 votes to do so in the past. But it doesn’t take 60 votes to pass a bill, it takes 50 (assuming Joe Biden gets to cast the tiebreaking vote). It takes 60 votes merely to prevent a filibuster. So I suppose the question becomes whether or not Democratic Senators will be willing to filibuster Democratic bills, and I’m inclined to think the answer to that is no. I can certainly see Mary Landrieu and Jon Tester voting against, say, a universal healthcare bill, but I can’t really see them voting to filibuster it. To do so would be to basically prove your uselessness to the national party, and probably leave you hanging out on your own limb. And Democrats in red states really can’t afford that. They need DSCC and DNC money to be competitive in re-election years, and the party leadership would do well to remind them of that.

Also, it’s worth considering that not every Republican Senator left over is going to be a rock-ribbed right-wing ideologue. Susan Collins, for example, looks to be headed for re-election in Maine, and she’s indicated that she’ll support Obama’s healthcarepan in the Senate. So even if there were a few defectors from the Democratic ranks, it seems likely that at least a couple of Republicans could be found to make up the difference, as thereare plenty of them who need to burnish an image of being a moderate, if not an outright liberal, Republican.