I know that it is about a year and a half out but
here is an article that expresses that New Hampshire GOP supporters are having a hard time getting excited about the prospective GOP candidates. That could mean that whoever gets picked will have a sizable portion of the Republicans pissed off at the decision, resulting in some of them voting for a third party, Democrat, or staying home. Especially if it is someone like Romney where teabaggers will throw a fit, causing some unrest.
Edit: It was talked about as to why I thought Obama was better than that for showing his birth certificate. Most birthers are Republicans. By Obama showing off his birth certificate, all he did was placate a group who was never going to support him in the first place. It wasn't like birthers would say "Oh, well, i guess he sure showed us! Obama 2012!!!" Unsurprisingly, few were left satisfied with some people saying "where's the
real birth certificate?" and some are now pushing further, wanting Obama to show off his grades. I'd venture to say that the vast majority (90%+) of birthers are dyed in the wool racist fucks who think that voting for a black man is voting for a black man to put his BBC in their chaste fair haired teen daughter's ass. These people were never worth placating.
The Kerry situation is completely different but I too thought that it was best that he never bothered to address it. The birth certificate and the Swift Boat for Truth or whatever the fuck that was called is just red meat for Republicans and right leaning independents. These Democrats only stand to lose face if they do something about it.