John Dickerson took perhaps too long to get to this paragraph, and he wrote it through gritted teeth, but he does put a finger on the central problem for the Obama administration right now:
The substantive differences between the president and Republicans on the budget may be insurmountable, but now it seems like even if the pipe dream of a substantive budget agreement could be reached it wouldn’t be enough. Even if Republican senators can engage in a trust-building exercise with the White House, how can they convince their constituents that the president is offering them a fair deal on the budget? A poisoned well is now roiling. Any Republican who tries to convince their constituents about a deal will now likely get funny looks. Their constituents would wonder why they were engaged in negotiations with an administration that has told evolving stories about its response to the attack in Benghazi and that houses an IRS targeting conservative groups.