Why would Obama try to make the election about himself?

All this means that the risk of Obama turning off voters who might otherwise come out and vote for Democrats is maybe not that big. On the other hand, these are close races; small margins matter, and in a state like Arkansas, which used to be a solid blue state but has tilted redder and redder in recent years, why give wavering Democrats an excuse to vote against Senator Mark Pryor?

It might have something do with the kind of voters to whom Obama is speaking. Having stipulated that swing voters don’t really exist, the trick to winning is to maximize base turnout. For Democrats in the South, that means black voters. Obama’s approval ratings may be in a serious slump, but he remains very popular with non-whites. Over the summer, Gallup had his approval among black voters at more than 80 percent. He also polls strongly among non-white voters more broadly. That’s why, as my colleague Molly Ball reported in August, Democrats are pouring resources into voter-mobilization efforts, signing up new voters and trying to squeeze as many votes as possible out of places like Pine Bluff, Arkansas.