Political scientist Andrew Gelman urges Mitt Romney: forget politics, choose the best person for the vice presidency—because it's not as if there's any political benefit to be found from the selection anyway.
During this lull in the campaign season, I'd like to repeat my recommend to presidential candidates that the best way to choose a vice-presidential nominee is to forget about ticket-balancing, shock value, winning the news cycle, and all the rest, and instead go for quality.
John Edwards, Dan Quayle, Dick Cheney, Sarah Palin, Joe Biden, Aaron Burr, . . . What does this gang of political punchlines have in common? They were all major-party nominees for Vice President. Presidents and presidential candidates, by comparison, don’t seem so wacky. There was Nixon, but he counts in the vice-presidential ledger too. And there have been failed presidencies (Jimmy Carter, George W. Bush), but these dudes aren’t political jokes along the lines of John Edwards.
At the same time, there's not much evidence that a VP choice provides electoral benefit. On one hand, we've estimated the VP home-state advantage to be about 3 percentage points, enough to win Ohio perhaps (and I've heard people credit Lieberman for Gore's popular-vote victory (estimated at approx 20,000 votes if all the ballots had been counted) in Florida in 2000). On the other hand, actual choices have included probable big-time vote-losers Quayle and Palin. So the electoral benefits would seem to be a wash at best. As a political scientist, I don't see the evidence that a campaign can improve its chances with an outside-the-box Vice-Presidential nominee.
Put all this together and it leads to the suggestion that a presidential candidate should pick as running mate the person he thinks would be best qualified to become president, if that were to be necessary.
Think of it this way: it's tough being a politician. No matter what your goals are, you're always having to compromise. The vice-presidential nomination is one place where playing politics doesn't seem to work. So I suggest forgetting the cleverness and forgetting about the idea that voters choose candidates based on their looks, and just picking the person you actually think would do the best job. Ruling out the Quayles, the Bidens, and the Palins . . . that wouldn't be such a bad idea, both as politics and as policy.