The powers that be seem to have decreed this Evan Bayh Week on the veep speculation front, and Nate Silver has a nice post (from which the above chart is drawn) questioning the conventional wisdom that Bayh is a Republican in a Democrat's clothing. As he puts it, "there is no senator more liberal than Bayh in any state more conservative than Indiana." This is somebody from a deep red state who has voted against extending the Bush tax cuts; against confirming John Bolton, John Roberts, and Sam Alito; against the gay marriage amendment; against cloture on cutting the estate tax; in favor of comprehensive immigration reform; in favor of S-CHIP expansion; in favor of stem-cell research; in favor of restrictions on detainee treatment; and in favor of the Iraq troop-withdrawal funding bill. He even opposed CAFTA. It's true that he sided with Republicans on tort reform, partial-birth abortion, and a flag-burning amendment, but do Democrats really want to be the kind of party that makes litmus tests out of those issues?
There are two more legitimate, and related, concerns, that can be leveled against Bayh--that he voted for the Iraq war, and that his relative liberalism of the past few years isn't authentic (though how important authenticity in policy views is is certainly open to debate). Bayh's voting record has been distinctly more liberal in the current Congress and the previous one than it was before that, presumably (at least in part) because Bayh had begun contemplating a run for national office. But it's also true that the American public has apparently become at least somewhat more liberal in the past few years than it was before that. (And making a litmus test even out of the war vote might alienate the broad majority of voters that supported the war at the time.) Surely Bayh could give a convincing monologue to the effect of, "Yes, my views have evolved in response to events. Yours probably have, too. The question is, why have John McCain's views evolved in the opposite direction?"
One final point in Bayh's favor is that of all the all the names being prominently floated in the veepstakes, Bayh might be the only one who stands a realistic chance of swinging a state to the Democratic column. In most cases, the notion that a veep pick can swing a state is overblown, but there are a handful of circumstances under which it seems to be more likely--particularly when the state is a relatively small one with a tradition of retail politics, and when the politician is such an established name that voters feel a real sense of loyalty to him or her. Indiana may be at the borderline of being too large, but by all accounts Bayh commands a type of respect there that's simply on a different level from what, say, Tim Kaine would bring in Virginia. Putting him on the ticket is probably still worth, at most, three or four points in Indiana, but this year that could end up being enough to give the state to Obama.