When Muhammad Ali died, in June, 2016, Donald Trump tweeted, “A truly great champion and a wonderful guy. He will be missed by all!” Alert readers recalled that, just six months earlier, Trump had tweeted this: “Obama said in his speech that Muslims are our sports heroes. What sport is he talking about, and who? Is Obama profiling?”

Perhaps this was meant to stand as evidence that Trump is in possession of a mind unblessed by coherence or knowledge. Or possibly it meant the opposite—that Trump knows precisely what he is doing, that he is willing to say absolutely anything that will, in the moment, work in his perceived interest, and to hell with all else. This perceived self-interest is almost certainly the reason for his ugly outbursts in recent days directed at African-American athletes. Hatred, pitting one group against the other, is his political instrument. He envisions his base, on couches and stadium bleachers, booing the likes of Steph Curry, Colin Kaepernick, and LeBron James. And he believes that the numbers are with him.

The N.F.L.’s Protest of President Trump

And so it’s a good moment to recall the events of a half century ago. When Cassius Clay changed his name to Muhammad Ali, and when he later refused the call of the military during the war in Vietnam, he was not universally cheered. Hardly. Ali was not prepared to give his life, or kill Vietnamese, on behalf of a society that barely valued his life or that of his fellow-black men and women. Or, as he put it, “Why should they ask me to put on a uniform and go ten thousand miles from home and drop bombs and bullets on brown people in Vietnam while so-called Negro people in Louisville are treated like dogs? . . . If I thought the war was going to bring freedom and equality to twenty-two million of my people, they wouldn’t have to draft me. I’d join tomorrow. But I either have to obey the laws of the land or the laws of Allah. I have nothing to lose by standing up for my beliefs. We’ve been in jail for four hundred years.”

On April 28, 1967, at the U.S. Armed Forces Examining and Entrance Station in Houston, Ali, standing beside twenty-five other nerve-racked young men called to the draft, refused to respond to the call of “Cassius Clay!” He said no, and was sentenced to five years in prison and released on bail. Boxing authorities quickly stripped him of his championship title and suspended his license to box in New York State. He was twenty-five years old, deprived of his livelihood.

Trump’s hollow post-mortem gesture of affection notwithstanding, Ali was hardly greeted by overwhelming praise. He was denounced by some of the most revered sportswriters and editorialists of the time. An editorial in Sports Illustrated said, “Without his gloves on, Ali is just another demagogue and an apologist for his so-called religion, and his views on Vietnam don’t deserve rebuttal.” David Susskind, a popular television host, called him “a disgrace to his country,” who “will inevitably go to prison, as he should,” and “a simplistic fool and a pawn.” Tragically, even Jackie Robinson, who had endured so much for the simple right to play baseball for the Dodgers, condemned Ali. “He’s hurting, I think, the morale of a lot of young Negro soldiers over in Vietnam,” Robinson said. “And the tragedy to me is, Cassius has made millions of dollars off of the American public, and now he’s not willing to show his appreciation to a country that’s giving him, in my view, a fantastic opportunity.”

“It’s hard now to relay the emotion of that time,” said Sonia Sanchez, the poet and civil-rights activist. “This was still a time when hardly any well-known people were resisting the draft. It was a war that was disproportionately killing young black brothers, and here was this beautiful, funny, poetical young man standing up and saying no! Imagine it for a moment! The heavyweight champion, a magical man, taking his fight out of the ring and into the arena of politics, and standing firm. The message that sent!”

Gerald Early, in his essay “Tales of the Wonderboy,” recalled Ali’s example for young people. “When he refused,” Early wrote, “I felt something greater than pride: I felt as though my honor as a black boy had been defended, my honor as a human being.”

It is hard to countenance Trump’s rote memorial tweet as anything but phony, an easy gesture toward the universally admired, and wounded, ex-champ who held the Olympic torch in Atlanta. But what could Donald Trump have thought of Ali’s insistence on his rights, and on the rights of African-Americans, fifty years ago? It is impossible to imagine that, in real time, Trump would have had anything other than disdain for the summit in June, 1967, when Jim Brown, Willie Davis, Bill Russell, Kareem Abdul-Jabbar (who was then Lew Alcindor), and other black athletes and community leaders assembled, in Cleveland, to declare their solidarity with Ali. (This was the early version of taking a knee or wearing a T-shirt reading “I Can’t Breathe.”) In 1971, the Supreme Court reversed the initial decision against Ali; two years later, Trump and his father faced lawsuits by the Justice Department for refusing to rent to black men and women.

When Barack Obama was asked last year about Colin Kaepernick taking a knee in protest, he spoke not as the leader of a political movement but as a holder of public office capable of a moral voice and with a duty to seek a unifying answer. Obama tried to bridge the gap between those who supported an athlete compelled to exercise his constitutional right to protest the deaths of young African-Americans at the hands of police officers and those who saw the national anthem as a tribute to, among others, those who had lost their lives as soldiers.

“I want [the protesters] to listen to the pain that that may cause somebody who, for example, had a spouse or a child who was killed in combat and why it hurts them to see somebody not standing,” Obama said. “But I also want people to think about the pain he may be expressing about somebody who’s lost a loved one that they think was unfairly shot.”

Trump has taken a radically different path. He cynically hopes that his political enemies will, like so many dolphins leaping to the bait, seize on his remarks as evidence of his support for one “side” and his disdain for another. He hopes that this will enthrall his base and conceal his legislative failures and the ongoing investigations against him. He is betting the sight of more professional athletes taking a knee will somehow lift him up. It might work for him now—but not for long.