Last week I suggested that liberals who shrug at the legislative accomplishments of Obama's first term do prominent Democrats, and the liberal cause more generally, a disservice. Many Democrats in Congress took political risks, and incurred sharp attacks from conservatives, by voting for measures like health care reform. If liberals don't stand behind them now, I suggested, lawmakers were less likely to take such votes in the future.

Among those responding was the liberal blogger Atrios:

I don't know the best way to get more liberal policies and more liberal people in office, but I also don't think the fortunes of Obama and Democrats depend much on how loudly I clap. More than that, if the volume of my clapping is that important then people should be spending a bit more time and money ensuring that I've got an adequate supply of hand lotion to keep my hands in peak clapping form.

I got plenty of emails to this effect, so I should probably clarify something. I was not suggesting that liberal ambivalence was the only reason, or even the primary reason, Democrats are likely to struggle this fall. I was suggesting that liberal ambivalence contributes to the Democrats' troubles and I think there's plenty of evidence to back that up.

Polls show that Republicans are more likely to show up at the polls this November than Democrats are. ("Democrats" are not the same as "liberals," I know, but I think the polls like this one from Reuters capture the gap in liberal-conservative enthusiasm, as well.) And, as more than one strategist pointed out to me, liberal reaction to Obama--in the blogosphere and in the country at large--helps to shape the broader media narrative on the Obama presidency.

Of course, liberals shouldn't be enthusiastic about the Democrats, let alone support them, if they think Democrats aren't fighting for liberal causes and at least having some success. But that's a different argument.