From a friend in DC Republican circles ...

I think you may be missing a key element of McCain's strategy. Remember, he has NO national ground game to counter Obama's vaunted field organization. No Bush-style 72 hour GOTV operation, no large and disciplined staff -- just a small core staff and media operation. In order to win without a ground game he literally has to destroy Obama as a viable alternative -- it isn't enough to just get close. That means the ads will be harder edged, more plentiful and more relentless than we've ever seen. I think Mark McKinnon realized that early on, and didn't want to be the guy to do to Obama what has to be done to win, as that person will become a political scourge (a la Atwater) when all is said and done, even if it works.