The Washington Post has a very revealing article about the failed debt negotiations last year:
Obama, nervous about how to defend the emerging agreement to his own Democratic base, upped the ante in a way that made it more difficult for Boehner — already facing long odds — to sell it to his party. Eventually, the president tried to put the original framework back in play, but by then it was too late. The moment of making history had passed.
In other words, they had a deal, then Obama tried to unilaterally change it in his favor, and killed the whole process by his bad faith. What a shock.