The Nazi analogy has long been recognized as the crudest and dumbest form of argument, but it is enjoying a renaissance.

Former CIA Director Michael Hayden notoriously tweeted a photo of Auschwitz-Birkenau as a response to family separations at the border. Upon a report that parents at the border were being told that their children were being taken to get bathed and disappearing, Chris Hayes of MSNBC tweeted, “What does this remind you of?” Soledad O’Brien chimed in, “Welp, I guess we’ve put to rest the question: ‘Nazi Germany: Could it happen here in America?’ ”

I have a relaxed attitude toward harsh political rhetoric, but Nazi analogies are over the line. You don’t deal with Nazis or tolerate Nazis. You do to Nazis what happens to them in the gruesome Quentin Tarantino film “Inglourious Basterds.”

Progressives imagine that they are protecting our system when making these and related charges, but they are really losing faith in it themselves and undermining its legitimacy.

A trope is to loosely associate something President Trump has said with Adolf Hitler or some other dictator. Kumail Nanjiani, a comedian with more than 2 million Twitter followers, objected to Trump’s contention that illegal immigration brings criminals into the United States. He said Hitler “focused on crimes by Jews,” and this is what brought on Nazi Germany over time.

Actually, Hitler was named chancellor in January 1933 and immediately acted to curtail individual rights and repress Jews. He gained full dictatorial powers via the Enabling Act in March 1933.

By comparison, Trump in his first year and a half in office has tweeted, called the press names and, yes, highlighted crimes committed by illegal immigrants. Unpresidential? Yes. Disturbing? At times. Fascist? No.

In “How Democracies Die,” Steven Levitsky and Daniel Ziblatt write, “Like Alberto Fujimori, Hugo Chavez and Recep Tayyip Erdogan, America’s new president began his tenure by launching blistering rhetorical attacks on his opponents.”

Well, yeah, and these comparisons would be apt if Trump went on to purge and jail his opponents.

Levitsky and Ziblatt believe the best scenario for democracy is that Trump loses. A darker future is that “a pro-Trump GOP would retain the presidency, both houses of Congress and the vast majority of statehouses.” To do this, Republicans would have to … win elections, which is an odd thing for an anti-democratic party to do.

The worries about Trump as fascist dovetail with critiques of our system itself as undemocratic. These will become more prominent as Trump moves to nominate his second Supreme Court justice.

For progressives, this is another sign of “minority rule.” But Republicans get to nominate and confirm Supreme Court justices because they won the presidency and retained control of the Senate in a hard-fought national election.

It is true that Trump won despite losing the popular vote, but the Electoral College is nothing new or untoward. Our system will presumably look much better to progressives if Democrats go out and win some elections. You know, like the alleged fascists do.

Rich Lowry is editor of National Review. Talk back at lettersto editor@bostonherald.com.