Obama has a Teflon coating, for now. Nothing will stick.
McCain is a weak orator, laying aside his policies and positions. Why waste energy and money tilting at a windmill?
Let the Obabamaboil fill with toxic pus until it ruptures of its own accord.
McCain is a weak Tele-Prompter reader. He does well in town-hall settings, microphone in hand, when he speaks without a script responding to unexpected questions.
Without a script to read, Obama is a stuttering gaffe-machine.