Talk about a flip flopper--McCain is one of the worst. There is no principled stand that he has ever taken that he hasn't changed his mind and now goes for the other side. Whether it was on taxes, immigration, oil drilling, abortion or the dangers of the Religious Right -- he's changed his views.
Usually, I think that politicians who change their mind when the facts change show maturity, judgment and flexibility. I respect that as a person gains more experience and knowledge, they might adjust their stands. But those are not McCain's reasons. He has only changed to suit the prevailing winds of the presidential campaign.