Look at the facts

Myths and Tall Tales Of the 2008 Election debunked by exit polls.

Bradley effect, anyone? How about race? Obama lost the white vote 55-43, but Kerry did worse (58-41.) In fact Obama did better with white men (losing 57-41) vs Kerry (62-37) and white women (losing 53-46 for Obama, 55-44 for Kerry), suggesting something we repeatedly came back to. People may be racist, but they didn't lie about it to pollsters.

And much more spelunking the data.