The speed of America’s moral descent under Donald Trump is breathtaking. In a matter of months we’ve gone from a nation that stood for life, liberty and the pursuit of happiness to a nation that tears children from their parents and puts them in cages.

What’s almost equally remarkable about this plunge into barbarism is that it’s not a response to any actual problem. The mass influx of murderers and rapists that Trump talks about, the wave of crime committed by immigrants here (and, in his mind, refugees in Germany), are things that simply aren’t happening. They’re just sick fantasies being used to justify real atrocities.

And you know what this reminds me of? The history of anti-Semitism, a tale of prejudice fueled by myths and hoaxes that ended in genocide.

First, let’s talk about modern U.S. immigration and how it compares to those sick fantasies.

There is a highly technical debate among economists about whether low-education immigrants exert a depressing effect on the wages of low-education native-born workers (most researchers find that they don’t, but there is some disagreement). This debate, however, is playing no role in Trump policies.