Poor states v. Rich states

Kevin Drum points to a paper entitled "Rich state, poor state, red state, blue state: What's the matter with Connecticut?" by Andrew Gelman, Boris Shor, Joseph Bafumi, and David Park. The paper finds that the rich are more likely to vote Republican than the poor. Nothing startling there. But, the paper also finds that the propensity for the rich to vote Republican is much stronger in the poor (mostly southern) states than in the rich (mostly northeastern) states. The graphic tells it pretty clearly. In the wealthiest state in the country, Connecticut, the rich are almost as likely as the poor to vote Democratic.