I don't think he did "go wrong." Certainly he hasn't been perfect, but from 2009-2016, only a truly exceptional/lucky president would have been able to maintain majorities in both houses of Congress (esp. a Dem dealing with the "natural House gerrymander") and keep an approval rating above 50%. He definitely could have played the game of politics better since taking office, but you could say that about pretty much anyone, and I don't think there's any one major error that he made.
He might have been able to pass one more bill in 2009-2010 if he had known that the GOP would oppose him as
strongly as they did, but another piece of legislation might have resulted in an even stronger backlash in 2010. And since 2010, I don't think he could have done a better job with the Republican House in place (which is a depressing thought).
