If McCain plays it smart, he can use it against him either way. IF obama pins the blame on his "advisors" then McCain can say it's just another example of Obama being a bad judge of character in the people he relies on to advise him. He's got a solid track record of showing bad judgment now, and McCain better run with it. Obama's lack of experience, is giving McCain all the material he will need to beat him.
Agreed, it SHOULD be McCain's to lose. On the other hand, far too many vote for the cool guy who makes them feel fuzzy inside... oh yes, and what they think will be "free stuff" (e.g., health care, social security, etc.).