An opinion piece1 in the New York Times written by someone who apparently voted for Obama and was enthusiastic about his presidency, concludes with a few hypotheses to account for what went wrong. I found this one most likely:
A second possibility is that he [Obama] is simply not up to the task by virtue of his lack of experience and a character defect that might not have been so debilitating at some other time in history. Those of us who were bewitched by his eloquence on the campaign trail chose to ignore some disquieting aspects of his biography: that he had accomplished very little before he ran for president, having never run a business or a state; that he had a singularly unremarkable career as a law professor, publishing nothing in 12 years at the University of Chicago other than an autobiography; and that, before joining the United States Senate, he had voted “present” (instead of “yea” or “nay”) 130 times, sometimes dodging difficult issues.
1. Hat tip Friedman