See the difference? Most of the ad is Bill Clinton talking which means, worst case, people won't here him, but even the images it flashes to make Obama look Presidential. When it switches to attacking Romney, not only do they use the sound bite, but they also make sure that the quote is onscreen. And probably most importantly in an attack ad, no part of this ad could be turned around and used as a positive ad by Romney. Seriously guys, this is not that hard.