The significance of high-profile endorsements in a presidential race is certainly debatable, but I’m certain that the Obama campaign was thrilled to pick up Sen. Bob Casey’s (D) support yesterday in Pennsylvania. Casey’s a major player in a key state; he may help Obama connect with white, working-class voters who’ve been skeptical about his candidacy; and the timing of the announcement helps feed the impression that Obama is surging ahead.



But I nevertheless think talk about Casey as a potential running mate for Obama is misplaced. Noam Scheiber makes the case for the pairing.

[Casey] may not be a star in the Senate, as Eve points out. But he’s popular with the people Obama is weakest among, and who, if Obama were the nominee, would be at greatest risk of defecting to McCain. (Also, don’t confuse inside-the-beltway reviews with home-state appeal.)

Pennsylvania defections are a real concern for Obama given how close the state’s been in recent elections. It’s a state that, under any conventional electoral map, the Democratic nominee has to carry. I’d bet the idea of putting Casey on the ticket has come up in Obamaland in recent days. […]

Which brings me to the next point: I’m guessing the audience for this endorsement is Casey’s fellow superdelegates as much as it’s voters in Pennsylvania. It says to the supers: “Don’t worry about white working-class defections. Bob Casey is going to help me lock down that demographic, and we’re not going to have trouble holding this state.” That may or may not be true, but it does send a powerful message. (Not as powerful as Obama actually doing well among white working-class voters in the primary, but still pretty powerful.)

Andrew Sullivan, independent of Scheiber’s argument, also touted Casey as “another interesting one to put on the veep list,” in part because Casey is a “pro-life Catholic from Pennsylvania.”

It’s not a ridiculous pitch, but I’m having trouble going for it.