A common last ditch effort in a heated political debate to steer the argument back in one's favor by declaring your opponent's position to be that of Adolf Hitler.
Often times this is done with little thought as to whether or not adolf hitler was for or against a particular side. Who cares about logic it's just fun to insult your opponents by likening them or their beliefs to tyrannical despots.
If you wish to play the Hitler Card and not look like a total tool here's some examples of Adolf Hitler's stances or at least what he claimed publicly.
He was For: abortion, capital punishment, censorship, eugenics, gun control, racial purity, and vegetarianism.
He was against: atheism, capitalism, communism, democracy, drinking, the disabled, feminists, Jews, Jehovah's witnesses, Gypsies, homosexuals, labor unions, pornography, prostitution, psychoanalysis, and smoking.