I think Maureen Dowd is actually on to something:
Asked about his friendly relationship with the former Weather Underground anarchist William Ayers - an association that The Wall Street Journal suggests could turn into the Swift Boat of 2008 given Ayers's statement that "I don't regret setting bombs; I feel we didn't do enough" - Obama defended him with a line that only the eggheads orbiting his campaign could appreciate. Ayers, he said, is "a professor of English in Chicago." Obama has to prove to Americans that, despite his exotic background and multicultural looks, he shares or at least respects their values and understands why they would be upset about his associations with the Rev. Wright and an ex-Weatherman.
A lot of folks were perplexed by Obama's comparison of Rev. Wright to his grandmother, but when he compared Ayres to Tom Coburn--well, then we had a pattern. Obama doesn't view left-wing radicals the way the rest of the country does, he doesn't understand why anyone would be upset that he associates with them, and more than that he seems dismissive of any such concerns (it's just dirt on his shoulder). On this issue, Obama is out of touch.