Nate Silver @NateSilver538
Empirically it's generally best to treat unelected incumbents as open-seat races. — PolitiTweet.org
Nate Cohn @Nate_Cohn
Also it has always struck me that the two incumbents who have mounted late comebacks—Truman and Ford—had not previo… https://t.co/g8jcBdQBuN