I think it would actually backfire if we did this, but Dean's voice, image and style invites an easy morph to Hitler at the Nuremberg rallies. If we actually tried to run such an ad we (Republicans) would be hawled out of our homes and burned at the stake as "hate mongers." However, I don't think we have to. Simply showing old Howie will bring up that image for most thinking human beings.
The best ad that can be shown to guarantee the re-election of GWB is simply to show the dims speaking. I love it.