The American Left is done arguing.

Liberals' censoriousness flared up again this past week, with multiple calls to shut down debate using tactics both old and new.

It’s a troubling trend. Conservatives used to mock the “snowflake” college students “triggered” by criticism and opposing viewpoints. These kids will be in for a rude awakening when they enter the real world, the line went. Nope. They’ve brought this silliness with them, and it’s infected the whole Left. (It could infect the Right too.)

The tried and true tactic on display this past week is simply to declare any voice to the right of center as illegitimate.

“I understand the short-term incentives for Bernie Sanders and Pete Buttigieg to appear on Fox News,” wrote former Obama administration spokesman Dan Pfieffer, “but putting an imprimatur of legitimacy on one of the most destructive forces in American politics has long-term consequences.”

Fox must be declared illegitimate, this mindset prescribes, leaving television watchers with nothing to the right of Jake Tapper.

A far more innovative method of censoriousness was rolled out this week by liberal politicians and commentators. The tactic is to declare criticism to be incitement to violence that endangers the lives of the liberals being criticized. Incitement to violence is just about the only type of nonslanderous speech that does not enjoy protection of the First Amendment. So until you can abolish the First Amendment, just declare everything "incitement."

The recent incitement-mania started with Rep. Ilhan Omar, D-Minn., but it spread beyond that. Now, liberal writers feel free to smear conservatives, and then if they receive any pushback, they declare the pushback itself to be incitement.

The Washington Post ran a piece on the Notre Dame fire by Talia Lavin — a writer with a history of falsely labeling wounded veterans as Nazis. Lavin lamented that “fast-talking far-right pundit Ben Shapiro called Notre Dame a ‘monument to Western civilization’ and ‘Judeo-Christian heritage.’”

This may seem innocuous to you, but to Lavin, “Western Civilization” and “Judeo-Christian” are bigoted code for anti-Muslim sentiment. Lavin implied that Shapiro was, in code, blaming the fire on Muslims (which he did not do), and concluded, “It is past time that those who stoke inflammatory rhetoric, knowing its potential to catalyze racist violence, were made to stop playing with fire — before it’s too late to control the inferno.”

In short, Lavin was deliberately lying about Shapiro as part of a censorship effort. When Shapiro criticized the op-ed, liberal watchdog group Media Matters was up in arms that Shapiro was “trying to rile up people against” Lavin and called it part of a campaign of “right-wing harassment.”

Around the same time, Media Matters published a piece criticizing pro-life National Review writer Alexandra De Sanctis for quoting an abortion clinic director in a story. Merey quoting the abortionist, Media Matters argued, “invited harassment” and “once again demonstrat[ed] the dangerous consequences of incendiary anti-abortion rhetoric.”

"Dangerous." "Incendiary." "Inciting." "Harassing."

Media Matters and others aren’t trying to argue against their conservative opponents. They are trying to brand all speech opposed to their own extreme viewpoints as incitement. It’s the latest tactic in their crusade against free speech. It shouldn't be ignored.