Mostly what Green finds is that the upper income whites who voted for Obama in 2008 are moving away from him in 2012. It makes sense.
In 2008 they were all "Let's give the promising black kid a chance" where in 2012 it's more like "We gave him the opportunity and he blew it. Who's next, that Mormon guy? Okay, let's give him a shot."
One could wish Americans took the Presidency more seriously, but it seems they don't. Who knows? Maybe they're right and we're wrong.