And Congress turned on them big time.
Furthermore, as Obama stated fairly often, the balance between Executive and Legislature has become horribly skewed in favor of the Executive since nuclear weapons made immediate response a necessity.
Finally, Obama in the Illinois Legislature got along better with rural lawmakers than he did with his fellow city lawmakers, and did better electorally in state politics when he ran in a predominately White district after failing in a Black district. He had great skills at bridging sides.
Obama clearly thought that Republicans would put the good of the country ahead of partisan politics if he showed the willingness to do the same and treat them with respect. And he wanted to restore the balance of powers.
We know there are Republican politicians who want this too. While they typically wait until they are retiring to admit it is their party's fault, they obviously must have known all along and were likely dying for a chance to return sanity to their party. However, I think Obama ran into two problems:
1. I believe the closeted (as in secretly sane) Republicans are badly outnumbered by those who just want to win at all costs.
2. Even if closeted Republicans had sufficient numbers, the rank-and-file went rabid at the election of a Black man. Given all the fighting that Boehner has done with the Teabaggers, I am really surprised he hasn't been primaried out of the party. In 2010 we saw a lot of Rightist extremists primaried out, not for being extremist, but for failing to season their extremism with *hatred*.