At 6:55 this morning President-elect Donald Trump tweeted. “Nobody should be allowed to burn the American flag — if they do, there must be consequences — perhaps loss of citizenship or year in jail!” Seemingly unprovoked—we’ve hardly seen a rash of flag-burning lately—it’s one more sign that we’re likely in for a wild ride over the next four years, assuming impeachment doesn’t occur first.

There’s a market for such views, to be sure, although most who voted for Mr. Trump probably are not in it. Liberty-loving Americans understand that there’s all the difference in the world between defending the right to burn the flag and defending the burning of the flag. It’s the difference between rights and values. Voltaire is said to have put it succinctly: “I may disagree with what you say, but I’ll defend to the death your right to say it.” (It’s probably apocryphal, but he should have said it!) Popular speech doesn’t need defending; unpopular speech does.

That principle is so basic to our political and legal order that the Framers of our Constitution embedded it in the First Amendment. And when there was a rash of flag-burning a while ago, the Supreme Court upheld the right to desecrate the flag, first in 1989 against a Texas statute, a year later against an act of Congress. Justice Antonin Scalia, lauded often by Mr. Trump, joined the majority in the first case. He wrote the opinion for the Court in the second.

But the issue does not seem to die. Republicans pressed for a constitutional amendment to ban flag desecration in 1995, shortly after they took over Congress following 40 years in the wilderness. And the proposed amendment arose again in 1999. Invariably, a misguided patriotism is behind such efforts. But as I concluded my congressional testimony opposing such an amendment in that last instance:

It is said also that the flag is special because men have fought and died for it. Let me suggest in response that men have fought and died not for the flag but for the principles it represents. People give their lives for principles, not for symbols. When we dishonor those principles, to protect their symbol, we dishonor the men who died to preserve them. That is not a business this Congress should be about. We owe it to those men, men who have made the ultimate sacrifice, to resist the pressures of the moment so that we may preserve the principles of the ages.

There doubtless will be occasions ahead when we will have to resist the pressures of the moment to preserve the principles of the ages. We must steel ourselves for that.