It’s interesting that so many of the people, like Mr. Trump, who are eager to punish flag-burners are at the same time so untroubled by speech that offends minorities, women and other Americans. They rail against any concern about that kind of speech as “political correctness.” But in this country, flag-burning is about as politically incorrect as anything you can do. Where is their courageous defense of speech now? Isn’t Mr. Trump the man who stood up for the freedom to say brutally unpleasant things? Who said, at the Republican convention: “I will present the facts plainly and honestly. We cannot afford to be so politically correct anymore.”

The court, by the way, has also declared that citizenship cannot be stripped away, not by Congress or the president, not in this democracy.

Some may choose to read Mr. Trump’s social-media rants as relatively meaningless — the ramblings of a sleepless id, unmoored from thought or knowledge but tuned to Fox News, which apparently was airing a piece on college flag-burners at about the time Mr. Trump sent his tweet.

But we don’t have the luxury of merely mocking someone who is now as powerful as Mr. Trump. Before you tune him out, remember what the right-wing propaganda site Breitbart was celebrating on Tuesday — that Mr. Trump’s social-media presence allows him to get his message to millions, bypassing “corporate media.” He has more than 16 million Twitter followers. With Twitter, Facebook and Instagram, he can feed lies and ignorance directly to 36 million people.

He tweets, he posts, he incites. He trolls. He commands a global platform and will soon be America’s commander in chief. But it has to be said, and said again: This is not normal. It demeans the presidency.