The underlying assumption is this: Vice presidential candidates add votes in their home state. The right VP pick can help carry a competitive state, the thinking goes, or put an uncompetitive state into play. Knowing that, a presidential candidate would be foolish not to use this strategic opportunity to try to pick up a key state in the Electoral College. At a minimum, the list of pros and cons for each vice presidential finalist must include his or her potential to deliver a home-state advantage.
Like all unquestioned shibboleths, it’s come to seem almost a law of nature by now. Analyzing news coverage between 2000 and 2012, we found that journalists invoked geographic strategy in about 50 percent of their profiles on potential veep candidates. But it’s wrong. According to our analysis of election and voter data over the course of a little more than the past century, a vice presidential candidate’s state of residence generally has no effect on how a presidential candidate performs in that state. The vice presidential home state advantage is, essentially, zero.
On a related note, I should say that it drives me crazy when people start talking about effective senators, like Elizabeth Warren or Jeff Merkley, being named as vice presidential candidates, and this obviously goes triple when it would turn a blue Senate seat red (as with Sherrod Brown.) Vice presidential picks are essentially irrelevant politically, and why would you want to downgrade an effective senator to vice president? I never understand why this is supposed to be a good idea.