I'd talked before about getting out of the way of a message. Take a look at this ad: [youtube=http://www.youtube.com/watch?v=Zns-K8XrOAk&feature=player_embedded]
Visually it's not just boring it's ugly, but it's message comes through loud and clear.
Now I don't know what the relationship is between Pat Quinn & Harold Washington or what folks in Illinois think of Harold Washington, but that's as devastating a critique as you can get. The only touch I would have liked to see is the context of the interview with Washington -- was that a campaign sponsored tirade or a news interview?
Why does it make a difference? Because it goes to motivation, if he was interviewed by the campaign it makes me more suspect about what he's saying. If it was "news" then it makes it more honest.
This ad is pretty harsh, but I think the extent to which is effective is the extent to which the messenger is believed and seen as objective. Looking at it from afar is seems to work, but up close there may be more than meets the eye, if there is, then it's the type of attack that can come back and bite a campaign.