Despite nice charts about policy and message and all that, elections turn on the economy. If the economy is doing well, the party in charge will stay in charge. If people are scrambling to pay their mortgage and have homes that are decreasing in value, they'll vote for the other guy. Incumbents still have a huge advantage, but in tight races, the outsider party will win. All this happens, despite the fact that political officials have largely no control over major swings in the economy.

That's American politics in a nutshell. Class dismissed.

So, what's going to happen in November? What's going to happen in two years? The economy is still in the dumps, and all indications are that it will stay sucky for a long time. Not a good scenario for Democrats.

Matt Yglesias and Kevin Drum look at a recent survey by the Washington Post that shows that even though a slight majority of people believe that Democrats better represent people like them, more people say they will vote for Republicans for Congress.