According to Jodi Kantor and Michael Powell, "A Strained Wright-Obama Bond Finally Snaps," in this morning's Times, this is the explanation of the final break between the candidate and the clergyman:
"As Mr. Obama told close friends after watching the replay, he felt dumbfounded, even betrayed, particularly by Mr. Wright's implication that Mr. Obama was being hypocritical. He could not tolerate that."
C'mon Barack: your preacher said many truly awful things about America, certainly more awful than that one suggestion that you might be a phony.
Do not go vain on us.