He failed to appreciate the enormity, significance and nature of America's core problem
This is evidenced by his not putting this gang on trial for war crimes, but instead attempting to unify with them. He read that Lincoln brought opposing forces into his cabinet, so he thought he could do the same thing.
Just how wrong, how naive, he was - has yet to play out, but we already see indicators here and here that he's incapable. There is another possibility, that he's complicit, in which case calling him naive is far too generous.
Where are we headed now? Let's take a look around: Russia, Korea, China, China, China, the world economy, Afghanistan, Afghanistan, Iran, Pakistan, Pakistan, Africa, Israel, The world at large.
What must Obama come to terms with? That the arrogant, belligerent attitude of neoconservatism struck America like a plague, and he can be neither ignorant nor complicit any longer.