President Trump does not have the power to "revoke" licenses of television networks, nor to "challenge" them as he has suggested. The impotence of these threats, however, doesn't make them harmless.

By advocating censorship, Trump sways his supporters and followers towards the censorious views that have taken over academia and much of the Left. He thus weakens the Right's embrace of free speech and open debate and makes it harder for Americans of all stripes to disagree civilly. In the long run, this illiberal attitude towards the media and disagreement will hurt conservatism and Republicans and help the Left.

"Network news has become so partisan, distorted and fake that licenses must be challenged and, if appropriate, revoked," the president posted on Twitter. "Not fair to public!"

Networks like NBC do not need any "license" to operate. "Broadcast licenses" are issued by the Federal Communications Commission to parcel out the spectrum over which signals are broadcast through the air. A television network needs no license to produce, report, or send its journalism over cable or the Internet.

The impotence and ignorance of Trump's threats doesn't excuse them. Nor does it count as a defense to point out how Trump's supporters revel in Trump's fights with media, or that this sort of culture war is what he was elected for. Those points actually highlight the danger of the comments.

A national leader can and often does shape the thinking of his countrymen, for better and for worse. Trump is very influential among his strongest supporters. He helped turn huge portions of the public against Fox News during the Republican primaries, convinced them CNN was the enemy later on, and now has driven the NFL's popularity into the cellar.

When Trump hammers away with some strong opinion, he shapes the thinking of his followers. In this case, he's nudging millions of Americans into thinking that overly hostile media ought to be silenced. The First Amendment doesn't depend on public approval, but the broader notions of press freedom, free speech, robust debate, and civil disagreement do get their strength from public consensus.

We've seen this consensus erode on the Left, and nearly disappear on college campuses. Illiberal censoriousness is one of the biggest threats to American politics and culture at this moment. Trump's idle threats just worsen things.

Among Trump's supporters, many say this is exactly the point. They are tired of playing by the rules while the other side tramples all over them. This was Trump's appeal — he was our unrestrained, rule-breaking culture warrior.

If the immorality of this stance doesn't bother Trump or his supporters, the imprudence should bother them. Giving government more power helps the Left, which believes in the state. Trampling the Constitution benefits the Left, which has far grander plans for using the government to reshape society. And narrowing the bounds of permissible debate helps the Left, which will lose in an open and robust debate.

Sen. Ben Sasse, R-Neb., put it well in a response on Thursday. "Words spoken by the president matter." The president pining for censorship erodes free speech.