There are some good lights that an Obama presidency might be cast in, though they require a leap of faith not required by a McCain vote. Michael Gerson offers them below.
RealClearPolitics - Articles - The Irony of Obama
Note that he views the real danger as coming from the Congress which all informed voters know is where the real power, and potential for trouble, lays. I suppose it bears repeating; regardless of the outcome the Republic will survive. The Founders had the wisdom to ensure that any insanity only has a two year shelf life! And with a potential Obama presidency on the horizon, there will be nothing to inhibit the public from focusing it's complete attention on what portends to be an even less popular post-election Congress.
You want a prediction? If Obama wins the election, Rush Limbaugh's ratings will climb even higher, perhaps stratospherically.