yes John Stewart would destroy him. But i think the only real tact one can take when debating trump is just to state unequivocally "I am not going to debate facts. My opponent continues to lie about every point coming out of his mouth, and i'm not going to engage" and then start talking about whatever you want to talk about.
trump's whole thing is repetition. just keep repeating the same lies over and over and over and eventually it will sink in to some feeble brained morons that it must be true b/c he keeps saying it. So you have to do the same. just keep repeating how much of a liar he is. If the folks who are, lets say, willfully uninformed keep hearing over and over that someone is calling trump a liar, eventually they'll get all mad and be like "Why do they keep calling him a liar??!?!? a simple search of the internet and its plain as day....ope, well, okay so maybe not on the first couple pages of google but"
and who knows? it might just stick in their smooth brains that a preponderance of evidence that contradicts what they believe might actually have some merit.