On the relationship between freedom, societal norms and law, no one has yet improved upon Judge Learned Hand’s dictum: “Liberty lies in the hearts of men and women; when it dies there, no constitution, no law, no court can save it.”

Nevertheless, people keep suggesting that government should use its coercive powers to control free expression in the name of social peace.

The latest is Richard Stengel, Nelson Mandela’s biographer, a distinguished former managing editor of Time magazine, former chief executive of the National Constitution Center and former undersecretary of state for public diplomacy and public affairs.

When someone this experienced in politics and journalism joins the cause of laws against hate speech, it’s wise to pay heed, especially since his argument, presented in a Post op-ed last week, does make a serious point.

Defenders of America’s free-speech doctrine — which allows almost anything that doesn’t libel a narrow range of private individuals, directly incite violence or depict the sexual abuse of children — often rely on an analogy between public discourse and competitive markets. When competing freely, truthful, beneficial thoughts will prevail over false, pernicious ones.

Though deeply rooted in Anglo-American political and legal theory, this “marketplace of ideas” metaphor has never quite corresponded to reality, as Stengel notes. Now social media — where hate and lies spread unchecked, inspiring terrorists of all stripes — has definitively disproved it.

The United States should try legal “guardrails,” like those in Germany or France, to bar “hateful speech that can cause violence by one group against another,” according to Stengel.

It would be easy — too easy — to reply that European hate-speech laws have hardly eliminated intolerance or intergroup violence. To shoot another fish in the barrel: The federal government ban on proprietary trading by banks is about 1,000 pages long, including all the definitions and exceptions. It would be even more difficult to write a legally consistent ban on speech that “deliberately insults people based on religion, race, ethnicity and sexual orientation” — and only on that speech.

No doubt citizens struggle to distinguish lies from truth, as indicated by the studies of Internet-using teenagers that Stengel cites. But that is an argument against democracy generally. (Also against lowering the voting age to 16.)

Rather, the best response to Stengel is to concede there is market failure in the marketplace of ideas — and to explain why it doesn’t, or shouldn’t, justify calling for laws against hate speech.

The question is not whether regulation is needed, in finance or speech. The question is who should do the regulating.

Fundamental individual freedoms — what the nation’s founders considered natural rights — are not as strongly implicated in, say, securities trading, as they are in writing, speaking, painting, singing, tweeting, marching, flag-waving and, yes, Koran- (or Bible- or flag-) burning.

In this sense, the market metaphor, which bases free speech on its consequences, rather than on humankind’s intrinsic right to engage in it, needs reformulation:

There should be a strong presumption against using government to fix the idea market’s inevitable failures, as long as there are private-sector alternatives — including not only competing speech, as the marketplace of ideas metaphor implies, but also peer pressure and other informal restraints on expression that people find unacceptable.

For all its excesses, even political correctness beats governmental enforcement of acceptable discourse.

Whether we are better off when everyone reads the “Adventures of Huckleberry Finn,” or shuns that Mark Twain classic because it frequently employs the n-word is not the point. The point is that the only thing worse than “cancel culture” would be “cancel culture” enforced by your state, i.e., the local district attorney, police and jailer.

“It is important to remember that our First Amendment doesn’t just protect the good guys; our foremost liberty also protects any bad actors who hide behind it to weaken our society,” Stengel writes — as if the same did not apply to the whole Bill of Rights. The Fourth Amendment protects terrorist hideouts from warrantless searches; the Fifth lets rapists refuse to confess.

This is nothing new. “Bad actors” — domestic and foreign — have been exploiting freedom to undermine it since time immemorial. Generally that has been thought of as a reason to redouble commitments to civil liberty, thus denying “bad actors” a victory.

“The Russians understood that our free press and its reflex toward balance and fairness would enable Moscow to slip its destructive ideas into our media ecosystem,” Stengel notes. “When Putin said back in 2014 that there were no Russian troops in Crimea — an outright lie — he knew our media would report it, and we did.”

Substitute “Stalin” for “Putin,” plus a few other changes, and you have a paragraph about the Russian lies that caused the New York Times to deny the Ukraine famine during the 1930s.

We live in an era of globalized social media and globalized politics, much of it frightening and extreme. Judge Learned Hand’s spirit of liberty can guide us through it, while preserving democracy, social harmony and the natural right to speak freely.

Read more: