All Barack would have had to say to avoid being held responsible for saying what he probably in his heart believes is, "that years ago and my positions have naturally evolved." Instead, he made what could turn out to be a substantial blunder when he faces the scrutiny of a general election in the fall - he passed the buck, saying that his campaign manager had misrepresented his views. That comes across as being weak and disingenuous, and questionable considering his own handwriting appears on one of the forms. Besides, it was his campaign, and it probably had no more than a couple of staffers. If he couldn't keep them in line, what's he going to do with the free world?
Read about Barack's Questionnaires Disease in the investigation conducted by Politico.