Matt Yglesias sees politics as a zero-sum game (a popular blogospheric notion):

The idea that there can be “bad news” for Democrats but “worse news” for GOP betrays a basic failure to understand the nature of electoral politics, namely that it’s a zero-sum competition for power in which only one candidate can win any given race and only one party can hold a majority in any legislative body.

If new polls show public dissatisfaction with Democrats but greater dissatisfaction with Republicans, that’s good news for Democrats.

But I’m not so sure that’s necessarily true.

I imagine if we lived a world in which the Democratic congress had approval ratings in the mid 60s, we’d see a lot more moderate to moderate-leaning Republicans crossing over on key Dem legislation in order to get in on some of that love (ie, perhaps enough to override an S-CHIP veto).

The way things are now (with both parties hitting the mid 20s) there’s just no incentive.

Politics may be zero-sum in each election (one party wins and the other party loses) but not when it comes to actually legislating.

Which should kind of be, you know, the point of politics