And Mr Obama's hard-edged cynicism also helps to quell one of the biggest doubts about his candidacy that he is toonaive and soft-minded to hold the most powerful job in the world.
Mr McCain's ace in the hole has been his claim that his opponent is toonaive and inexperienced to be trusted with the big decisions that he will withdraw precipitously from Iraq to satisfy his liberal base and thereby undermine America's war on terror.