gotta give the mccain camp some props for this add.  Remember John Kerry and flip flops?  that seemed to work.  This is pretty much the same strategy.  Instead of a full 30 second ad of bashing obama, the ad is about 15-18 seconds of Obama "bashing" or "flip-flopping" and the remaining 12 seconds is positive for McCain.  Just a classic compare and contrast commercial.  I bet it will have some effect for McCain's camp.  American voters tend to respond more positively to these types of ads than the full 30 seconds of "this guy sucks."