Ronald Reagan enjoyed recounting the cynical jokes that citizens of the Soviet Union often told about life under communism. One of his favorites involved an American and a Russian who were arguing about the merits of their respective countries. As Reagan told it, the American said, “In my country, I can walk into the Oval Office, pound the president’s desk, and say, ‘Mr. President, I don’t like the way you’re running our country.’” The Russian replied that he could do the same thing. The American was surprised: “You can?”

“Oh, yes,” said the Russian. “I can go to the Kremlin, enter the general secretary’s office, pound his desk, and say, ‘Mr. General Secretary, I don’t like the way President Reagan’s running his country!”

If anything is a defining feature of a free society, it is the right of ordinary citizens to openly criticize, ridicule, or joke about government officials, however lofty or powerful. So when Anthony Novak of Parma, Ohio, decided to create a mocking parody of his local police department’s Facebook page, he was engaging in activity that goes to the core of American civil liberties — liberties that officers of the law are sworn to uphold.

But Parma’s police officers didn’t uphold Novak’s rights — they shredded them. They announced that the spoof Facebook page was being “investigated.” They claimed that “public safety” was at stake and got Facebook to identify the creator of the parody. They arrested Novak on charges of having broken a law that makes it a crime to “disrupt, interrupt, or impair the functions of any police … or governmental operations.” They jailed him for four days and got a warrant to search his apartment, where they seized his laptop, cellphone, hard drives — even his gaming consoles.

“When I woke up in jail … I thought, wow, I really screwed up here,” Novak said in an interview recorded by the Institute for Justice, the nonprofit public-interest law firm that represents him. “And then I remembered, wait, I didn’t actually do anything wrong.”

No, he actually didn’t.

When the case went to trial, the jury unanimously acquitted him. But when Novak subsequently filed a federal lawsuit against Parma police detectives for the abuse of his constitutional rights, the US Court of Appeals for the Sixth Circuit held that the police were protected by “qualified immunity.” Under that doctrine, police (and other government officials) are not accountable for violating a citizen’s rights — even if they do so in bad faith — unless their misconduct was plainly contrary to “clearly established” law. The appellate court held that since Novak didn’t include a disclaimer making clear that his page was a spoof, the police might have sincerely believed that what he posted on Facebook was illegal.

Now Novak and the Institute for Justice have appealed to the Supreme Court, arguing that if anything is clearly established in American law, it is the right to caricature, laugh at, or parody public officials.

Enter The Onion.

In an amicus brief that is simultaneously brilliant, hilarious, and serious, the noted humor website — which specializes in parodying traditional news stories — urged the high court to hear Novak’s case. In keeping with Supreme Court rules for friend-of-the-court briefs, it first identified itself and explained its own interest in the case. It did so, of course, in its signature deadpan style:

“The Onion is the world’s leading news publication, offering highly acclaimed, universally revered coverage of breaking national, international, and local news events,” the brief began, mentioning its “daily readership of 4.3 trillion” and its ownership of “the majority of the world’s transoceanic shipping lanes.” Its interest in the case, it said, is straightforward: “The Onion’s writers … have a self-serving interest in preventing political authorities from imprisoning humorists.”

But there was nothing humorous about what Parma’s police did to Novak, and it’s alarming that an appellate court would give the cops a pass because someone satirized them with a straight face.

“The Sixth Circuit’s ruling imperils an ancient form of discourse,” the brief notes. “The court’s decision suggests that parodists are in the clear only if they pop the balloon in advance by warning their audience that their parody is not true.” But parody depends on its ability to “plausibly mimic the original.” If the court of appeals ruling is allowed to stand, it would mean that parody is entitled to First Amendment protection only if it is stripped of the very element that makes parody work in the first place.

Novak and his lawyers are asking the Supreme Court to hear their case for reasons of constitutional clarity. The Sixth Circuit’s understanding of the law is contradicted by that of the Fifth, Ninth, and Tenth Circuits, and only the high court can resolve the split. More ambitiously, the petitioners want the justices to reconsider the whole concept of qualified immunity, a doctrine with no basis in the Constitution or statutory law, and one that all too easily lets malicious officials off the hook.

At a minimum, however, the Supreme Court can use this opportunity to confirm that parody is wholly protected by the First Amendment — period. In all candor, Novak’s pretend Facebook page wasn’t all that funny and a few Parma residents apparently didn’t get the joke. But under the Constitution, that doesn’t matter. It isn’t only Onion-caliber parodists who are entitled to crack wise at the expense of their local police department. And cops who wage spiteful vendettas against would-be comedians shouldn’t be allowed to claim that the parodist had it coming for failing to spoil the punchline.

Parody is an essential form of social and political criticism. It is as old as Aristophanes and as contemporary as the most recent Weekend Update on “Saturday Night Live.” It is a powerful tool for exposing folly, tweaking the high and mighty, calling attention to injustice, and broaching unpopular truths. It can be a vivid means of weighing in on controversies of the day. In April 2016, the Boston Globe Opinion section published a parody version of the newspaper’s front page, dated one year in the future, to convey with eye-catching immediacy what it thought a Donald Trump presidency would look like.

At its best, parody enriches public debate by illuminating the status quo from an unfamiliar angle. Jonathan Swift’s “modest proposal” in 1729 for preventing Irish children from becoming a financial burden on their parents (he recommended selling them to be eaten) was both a grisly piece of satire and a brutal comment on English attitudes toward Ireland’s poor. Nearly three centuries later, that essay is still discussed and has lost none of its shock value — a striking demonstration of the power of great parody.

Swift’s reputation is in no danger of being eclipsed by Novak’s parody. But that makes no difference to the First Amendment and should have made none to the police. What happened in Parma was no joke, and the Supreme Court ought to take up this case to say so.