Political scientists and economists love natural experiments, the all-too-rare situation in which normal events set up a comparison between competing ideas. They can be pretty convincing because we can build a case using with real data, not just speculation about what ought to happen if the world adopts our wonderful ideas. Minnesota and Wisconsin are roughly comparable and took different directions in recent elections. Here are the results. You can guess that since I post it, progressives outperform the teaparty conservatives.