Probably can't be done but it should really be illegal to compare one's political opponents to Nazis in this country unless you can show that they actually advocate exterminating an ethnic minority.
If Americans are too stupid to toss these people-- the politicians who can't resist comparing their opponents to Nazis-- out on their asses for this really, really appalling act of desecration of the memory of all those who died at the hands of the real Nazis, unfortunately, there's not much you can do about it except consider the credibility of some bone-faced politician who glides easily into these kind of hysterical slanders.