The ad would not be nearly as effective as you think. As has already been demonstrated, release of the birth certificate does not guarantee an end to the debate about Obama’s legitimacy. Plenty are still obsessed with somehow reaching the conclusion that the President is not the President, and it doesn’t matter what the White House does.
While not a certainty, it’s perfectly reasonable to expect that Lakin would just resort to the “Obama’s mother wasn’t old enough to confer citizenship” or any host of other tacts that the majority of voters will not hear or care about.
If you don’t think the ad would be effective you don’t know psychology. The right images and the right voice-over would devastate Obama irreparably.