Overall, I'm going with Atrios on this one. There are 2 sub-debates where I think Atrios and Co. are indisputably the "righter" ones:
1. Letting Lieberman off the hook sets a dangerous precedent where incumbents with support from the right are no longer expected to respect the will of their party members, as decided by primaries. In a political age such as this where people want to throw their weight behind the donkeys but are skeptical of their populism, unaccountable incumbents are a big problem.
2. (the more obvious one) Lieberman vs. Lamont isn't just about Lieberman or Lamont because there are no less than 3 House races at stake that Lieberman's campaign strategy of "get out the Republican vote" ipso facto jeopardizes. In other words, Lieberman's choice to flip CT Democrats the bird may cost House Democrats 20% of the gains they need to retake House leadership. Twenty percent.
There is, however, one notable place where I think DK is closer to the mark: Money, time, and labor allocated for Lamont/Lieberman (mainly by voters but also, I suspect, by the party campaign committees) is money that could've been spent elsewhere against actual card-carrying Republicans.
The problem for DK is that he's looking the wrong way when he says that, i.e., he's looking scornfully at the netroots when he should be looking at Joe Lieberman. It's not the netroots' fault that Lieberman's running as an independent and sapping Democratic resources; it's Joe Lieberman's fault. Nor did the netroots elect Lamont in the first place; Connecticut Democrats did. Is anyone going to say they were wrong for speaking their minds and expecting Lieberman to respect their wishes?
DK's very valid point that there is, in fact, resources going to this race that should've gone to others only exacerbates the fact that Joe Lieberman is doing tremendous damage to his party for defying their will in a perfectly legitimate primary and that nobody's fault but Joe Lieberman's.
UPDATE: Marshall has finally put his 2 cents in here. Like Atrios, he questions the "zero-sum" nature the resources spent on the race. Again, I really still don't agree. Certainly it's not a 1-to-1 ratio of, for instance, money to Lamont-money to Donnelly, but there most certainly is some opportunity cost involved in fighting the CT-Super Primary. There are people out there who are gung ho about the midterms and definitely going to give money to Dem candidates and would like to cut Webb 50 clams, but they're giving some (or all) of it to Lamont instead because they feel ousting Lieberman is a higher priority. If Lieberman weren't running, then what, they'd keep their money to themselves? I'll bet there's a ton of people in Connecticut in exactly this position.
Josh also sez:
What does irk me is that there's a tendency I see in a lot of liberal blogosphere to go from being against Lieberman, to being against anyone who supports Lieberman, to being against anyone who isn't sufficiently against Lieberman, to be against anyone who even raises a question about the emerging orthodoxy about this race.
Well, I would agree, and this makes a lot of sense to me, except I haven't actually seen much any of this. Or rather, I haven't seen anything that doesn't have a doppleganger on the other side. In fact, I'm tempted to say that the "I'm against anyone who dares question the supreme importance of CT-Sen. over all other races" Democrat is of the same feather as the "O Boy! I just Luuuuuuuuuv big government!" Democrat.
Chimerae do have feathers, right?