The Kerry Spot puts things in perspective:
Changing your mind — “the flip” — isn’t the problem. Even Bush has done it, on issues from steel tariffs to the Department of Homeland Security to campaign finance reform. Changing it back when the situation changes again — “the flop” — is a problem. It’s a formula for a back-and-forth policy, constantly shifting in the face of adversity. If you want to lead, you have to have a goal and you have to pick an approach and you have to stick to it, at least until you’re certain that the first approach won’t work. If you shift to a second, third, fourth and then back to the first approach each time you hit an obstacle, you’ll never reach your goal.