This language isn't merely ugly or repellant: These words belong to a particular tradition. Adolf Hitler used these kinds of terms often. In 1938, he praised his compatriots who had helped "cleanse Germany of all those parasites who drank at the well of the despair of the Fatherland and the People." In occupied Warsaw, a 1941 poster displayed a drawing of a louse with a caricature of a Jewish face. The slogan: "Jews are lice: they cause typhus." Germans, by contrast, were clean, pure, healthy, and vermin-free. Hitler once described the Nazi flag as "the victorious sign of freedom and the purity of our blood."

Stalin used the same kind of language at about the same time. He called his opponents the "enemies of the people," implying that they were not citizens and that they enjoyed no rights. He portrayed them as vermin, pollution, filth that had to be "subjected to ongoing purification," and he inspired his fellow communists to employ similar rhetoric.

In using this language, Trump knows exactly what he is doing. He understands which era and what kind of politics this language evokes ... "If you don't use certain rhetoric," he told an interviewer, "if you don't use certain words, and maybe they're not very nice words, nothing will happen."

His talk of mass deportation is equally calculating. When he suggests that he would target both legal and illegal immigrants, or use the military arbitrarily against U.S. citizens, he does so knowing that past dictatorships have used public displays of violence to build popular support. By calling for mass violence, he hints at his admiration for these dictatorships but also demonstrates disdain for the rule of law and prepares his followers to accept the idea that his regime could, like its predecessors, break the law with impunity.

These are not jokes, and Trump is not laughing. Nor are the people around him. Delegates at the Republican National Convention held up prefabricated signs: Mass Deportation Now. Just this week, when Trump was swaying to music at a surreal rally, he did so in front of a huge slogan: Trump Was Right About Everything. This is language borrowed directly from Benito Mussolini, the Italian fascist.

Several generations of American politicians have assumed that American voters, most of whom learned to pledge allegiance to the flag in school, grew up with the rule of law, and have never experienced occupation or invasion, would be resistant to this kind of language and imagery. Trump is gambling - knowingly and cynically - that we are not.

"Hate, it has caused a lot of problems in the world, but has not solved one yet." ---Maya Angelou