Ford = His pardon of non crimes for RMN.
Carter = Rabbit, Olympic athletes, panama canal, malaise speech, gas lines, Iran, lusted in his heart.
Clinton = When we got to the "Character doesn't matter" part by his supporters.
Bush 41 = Read my lips, no new taxes.
Gore = No legal controlling authority
Kerry = His post Viet Nam treachery
Dean = Never followed his antics very much, so the scream will do
Of course I do recognise a boilerplate overall JTS moment. It goes, "Hi I'm running on the Democratic ticket for...."
Actually, I think that Kerry jumped the shark when he hollered, "Bring It On!"