I think this points to the wisdom of the Obama strategy re: McCain.  Don't attack the man, don't attack his character, don't attack his wife, always give respect to his service and record--and tie him aggressively to the failed policies of George Bush.

McCain could end up finding himself in a tricky position.  The hard conservatives despise him because he has been legitimately a maverick: they think he's a traitor because of Gang of 14, campaign finance reform, his position on torture, his initial criticism of the Bush tax cuts.  Obama needs to limit his reach to the great ideological middle to whom those positions might be attractive.  

If it turns out that McCain's zigs to the hard right--re-supporting the tax cuts, his soulless re-embrace of Falwell et al, his promises for more Scalias and Thomases--are driving the middle away from him, Obama should be in a great position to pick them up.