John McCain is indeed flipping and flopping his way through some policy platforms versus what he signed on to in the past. But the all time bell-ringer for flip-flops is Senator Obama's back-turner on government-funded campaigning. Obama was unmistakable in his high-road desire to "aggressively" pursue matching government funding. But that was when he calculated that he would need the money and could lead a moral browbeat of his GOP competitor that the campaign-reform-obsessed popular media would willingly ride home for him. Today, Obama doesn't need the cash!
I suppose one could also suggest that Obama's cite of prominent economists to bash McCain's gas tax holiday is a flip-flop of sorts. After all, he doesn't query the same economists about his enthusiastic vote for the farm bill! Senator McCain bravely voted against it and undoubtedly won the day with economists everywhere.