Nate Silver @NateSilver538
@MattGrossmann @gelliottmorris @jbview @AJentleson FWIW, in the data we use for our Senate and House forecasts, it's not clear that the extremism penalty has declined at all since the 90s. It has a lot of confounders. For instance, one reason the incumbency advantage has declined is probably because the parties are more extreme. — PolitiTweet.org