Whipping up the crowd at a campaign rally in Alabama last week, President Donald Trump excoriated NFL athletes audacious enough to refuse to stand with hand over heart for our national anthem. He called upon NFL owners “to get that son of a bitch off the field right now.” On Tuesday morning, he doubled down: “Kneeling during the playing of our national anthem I think is disgraceful.”

Trump found it intolerable that NFL athletes would dare to act in ways he regarded as disrespectful of our national heritage. Yet the president and his defenders simultaneously express outrage when liberal activists oppose speakers they believe publicly disrespect minorities. Attorney General Jeff Sessions, for example, proclaimed at Georgetown University on Tuesday: “Protesters are now routinely shutting down speeches and debates across the country in an effort to silence voices that insufficiently conform with their views.”

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The First Amendment, it seems, is a tricky subject. And those who would use its precious principles only for their own political ends do much to damage our constitutional commitment to free and open debate.

How might these principles apply to our president’s own behavior? Alone among modern chief executives, Trump seems intent on publicly insisting that those who oppose him be punished. A recent example is his call for the firing of ESPN anchor Jemele Hill, who had the temerity to call Trump out as a “white supremacist” and a “bigot.” How do the constitutional standards of the First Amendment apply to such behavior on the president’s part?

We might think of this question, first, in terms of how a court would respond if a lawsuit were brought against the president. We usually understand First Amendment protections in terms of judicially enforceable rights, yet First Amendment doctrine applies to Trump only with great difficulty. This is because judicially enforceable First Amendment restrictions typically exempt what courts call “government speech,” which means that, so far as the courts are concerned, the government doesn’t need to be viewpoint- or content-neutral when it speaks. As the Supreme Court explained in its 2015 opinion in Walker v. Texas Division, Sons of Confederate Veterans: “Were the Free Speech Clause interpreted otherwise, government would not work. How could a city government create a successful recycling program if officials, when writing householders asking them to recycle cans and bottles, had to include in the letter a long plea from the local trash disposal enterprise demanding the contrary?”

When Trump speaks, it is as if the government were speaking. He can ordinarily say what he wishes. He can whip up frenzied opposition to Obamacare or NFL players. Yet there may nevertheless be judicially enforceable limitations.

If the president’s words are designed to trigger the legal suppression of citizen speech, he may likely be violating the First Amendment. The relevant case is the Supreme Court’s 1963 opinion in Bantam Books, Inc. v. Rhode Island. The decision concerned a Rhode Island commission charged with educating the public about obscene publications and recommending to the state attorney general the “prosecution of purveyors of obscenity,” as the court’s decision put it. As a formal matter, the commission did no more than engage in government speech that “exhorts booksellers and advises them of their legal rights,” but the Supreme Court nevertheless had no difficulty enjoining the commission’s activities, because “the record amply demonstrates that the Commission deliberately set about to achieve the suppression of publications deemed ‘objectionable’ and succeeded in its aim.” The commission “was in fact a scheme of state censorship effectuated by extralegal sanctions,” the court declared.

Perhaps we might draw an analogous conclusion about Trump’s remarks: The president has also engaged in a verbal campaign designed to suppress speech that offends him. We know that speech cannot be censored merely because it is offensive. As Justice William J. Brennan Jr. wrote in a 1989 case involving flag burning: “If there is a bedrock principle underlying the First Amendment, it is that the government may not prohibit the expression of an idea simply because society finds the idea itself offensive or disagreeable.” In some ways, Trump’s behavior is even worse than the Rhode Island commission’s. Whereas the commission aimed to suppress obscenity, a category of expression without legal protection, Trump’s ire is directed at core political speech protesting law enforcement’s unfair treatment of minorities. Trump’s allies have already begun organizing boycotts (for example, a “Turn off the NFL” campaign) to give teeth to the president’s intemperate attacks.

Yet the analogy to the Rhode Island commission is perhaps too quick. It was crucial to Bantam Books that the commission’s threats were backed by the law enforcement institutions of the state. What booksellers feared was that the commission would cause the state to initiate criminal prosecutions. For all Trump’s braggadocio, there is no indication that he is invoking the law enforcement apparatus of the federal government to harass or sanction NFL players who are taking a knee. Were such evidence adduced, Bantam Books tells us that Trump’s threats would violate the First Amendment. In fact, this conclusion would follow if Trump intended to activate any part of the vast civil and regulatory infrastructure of the federal government to retaliate against NFL players (or their employers) for their protests.

The same conclusion would also follow if it could be shown that Trump, using the considerable authority of his office, conspired with private groups to compel NFL owners to sanction players who take the knee. Insofar as Trump uses the power of his office, it does not matter whether he acts through the FBI or through private parties; he would still be suppressing speech under the color of state law and thus violating the Constitution. Trump skates close to this edge when he uses his official Twitter account to retweet calls for an NFL boycott.

Still, to date, we have no evidence to indicate that Trump has done anything more than verbally attack the speech of private citizens, who might suffer adverse consequences at the hands of those who are convinced by the president’s pronouncements. The situation is similar to what might happen if a president were to condemn in harsh and dismissive terms the publications of scientists who claim that smoking is unrelated to cancer. If these scientists consequently lose business possibilities or private foundation grants or consulting opportunities, they likely could not successfully sue the president. His condemnation would probably be classified as mere government speech, nothing more.

It follows that whether Trump has run afoul of the judicially enforceable First Amendment will very much depend on the facts proved in any lawsuit brought against him. Can it be shown that Trump is bringing to bear the law enforcement or regulatory apparatus of the United States? Can it be shown that he is using the prerogatives of his office to conspire with private parties to suppress speech? If the answer to either question is “yes,” then the president has violated the Constitution.

One further legal complication comes to mind. Suppose it can be shown that Trump is neither using government operatives to chill speech nor conspiring with private parties to coerce speakers, but that it can be demonstrated that private citizens “reasonably” believe that Trump is doing these things. Because it is so important to prevent chilling the political expression of citizens, would it violate the judicially enforceable First Amendment if the president acted ways that induced reasonable citizens to believe that he was breaking the law? To answer this question, a court would have to balance the chilling effects of presidential speech on private speakers against the chilling effects of judicial review on presidential expression. In the absence of “true threats,” as distinct from “rhetorical hyperbole,” I would put money on the proposition that courts would bend over backward to stay clear of the responsibility of supervising the political expression of official actors.

To analyze Trump’s recent behavior only in terms of how a court might rule in a hypothetical lawsuit, however, is to miss the deeper and more important constitutional values at stake in his recent outbursts. Our president swears to “preserve, protect and defend the Constitution of the United States.” A fundamental axiom of the Constitution is democratic self-government. Democratic self-government is a difficult and complicated concept, but at its root lies the idea of the peaceful self-determination of “We the people.” This short phrase contains many fundamental principles, among them that “we” commit to form one united “people.” Although we might disagree with one another, we pledge to maintain the peaceful integrity of our body politic by settling our differences through talking to one another, through forming public opinion and through creating institutions that enable our public opinion to shape government decision-making. By taking his oath, the president obligates himself to preserve and defend these basic propositions.

Trump’s attacks on the political speech of private citizens are inconsistent with the requirements of his office. It is striking that Trump’s insistent and recurring political instinct is to appeal to his base by constructing enemies—the press, Jemele Hill and now football players who kneel during the national anthem. Enemies are by definition excluded from the American body politic. They are excommunicated from “We the people.” Trump can disagree with his opponents, but he must always convey respect for their right to dissent. By casting them out as enemies, he undermines the hard-earned and necessary integrity of “We the people.”

The American chief executive is unique in that he is both a prime minister and a president, both a politician and a symbol of the overarching unity of the nation. Trump seems utterly oblivious to the latter role. When people observe that Trump seeks to divide the country rather than bring it together; when they complain about his inability to empathize with the suffering citizens of Puerto Rico or with oppressed African-Americans; when they are nauseated by his cruel and petty treatment of political rivals; when they are stunned by his narcissistic intolerance of dissent; they are in effect marveling at Trump’s blank incomprehension of his deeper responsibility to “preserve, protect and defend” the national unity that makes possible our constitutional government.

Trump is unqualified to be president because he cannot imagine a country in which individuals can reasonably disagree about things that matter. An intolerant nation is not a stable nation. Of course, no court will sanction Trump for his short-sightedness. But in the eyes of history, I believe it will prove Trump’s greatest constitutional failure.

Robert Post is Sterling professor at Yale Law School. This article is adapted from its original version, which appeared on the blog Take Care.