McCain's a demagogue. He's not interested in reasoned debate, he'll put Obama on the spot with emotional issues like Iraq and the "troops." Or Israel.
Obama can't win. If he responds honestly to McCain, he's gonna look like an elitist snob. Nothing wrong with being an elitist, he really IS smarter than McCain, his wife's smarter than McCain's wife - - but how's it look to admit it? If, OTOH, he tries to "out-redneck" McCain, he'll only piss off his base.
I look at it like this: Obama's being deliberately vague about his intentions, which leaves me uneasy because it means he can betray his base and say he never promised anything specific. So the base could get screwed. But I know he also is NOT tied to five more years in Iraq, not really tied to specific backing of Israel (never went as far as Hillary.) I'm willing to take a chance on Obama - - the chance that he won't betray his base, the people who want real change, but I know that betrayal is an ever-present possibility. Wouldn't be the first time. Bill Clinton betrayed his base when he shafted Lani Guinere.
When he says "change," I and a lot of others tie it to, NOT wedded to military solutions, endless killing and lying and invasions on behalf of Israel and/or Big Oil; NOT wedded to perpetual unconditional backing of Israel at the expense of Palestinians, Arabs and Muslims. THAT'S what "change" means to me.
To spell it out would spell doom. Why not pacify the morons, who are a large percentage of voters, and get in with the votes of those who really want "change?" I don't need to hear him debate McCain - - the issues have already been debated ad nauseam here and elsewhere. A debate would not shed light on the issues, but it could easily cost Obama votes by stripping him of the ambiguity he clearly can benefit from and take advantage of. The debate formats I have seen always put the demagogue at a decided advantage. Obama is the anti-demagogue, why fight on the demagogue's home turf and rules?