President Trump posthumously pardons Jack Johnson, boxing's first black heavyweight champion, during an event in the Oval Office on May 24, 2018. Trump is joined by, from left, Linda Haywood, who is Johnson's great-great niece, heavyweight champion Deontay Wilder, Keith Frankel, Sylvester Stallone, and former heavyweight champion Lennox Lewis.Susan Walsh / AP

Donald Trump corrected a misuse of justice when he issued a posthumous presidential pardon to Jack Johnson on May 24, 2018. But his pardon of Jack Johnson, which came 105 years too late, is not enough to address the scourge of racially motivated policing, or the entanglements of white supremacy and sexual regulation.

Over a century ago, in May 1913, an Illinois jury found the world-famous heavyweight champion guilty of violating the White Slave Traffic Act, popularly known as the Mann Act. Responding to public outcry against the prevalence of prostitution and stories of sexual slavery, Congress in 1910 criminalized the facilitating or persuading a woman to travel over state lines for the purpose of prostitution, debauchery, or “any other immoral purpose”—a broad and vague phrase that offered prosecutors a powerful tool to regulate fornication, seduction, or adultery. As lawyer Henry Dannenbaum argued, “Private use or public exploitation are both immoral, both are denounced by the state laws and moral sentiment, and they differ only in the degree of immorality.” Jack Johnson provided a tantalizing opportunity to test the relatively new law and, in the process, take down a defiant black man.

Boxing’s 1908 heavyweight champion, Johnson was an anathema to everything Jim Crow America represented. He was black, strong, fierce, a champion, and most dangerous of all, unapologetic about his sexual relations with white women. Known as much for his bravado and racial pride outside the ring as his skill within it, he soon became a flashpoint for the racial antagonisms that characterized an era of disenfranchisement, legal segregation, and white-on-black violence, in which the presumed rape of Southern white women by black men justified lynching. After he successfully defended his heavyweight championship in 1910 against white boxer Jim Jeffries in “The Fight of the Century,” cities around the nation erupted, with angry white mobs marching on black neighborhoods.

Johnson’s celebrity lifestyle consistently featured a white woman by his side. In 1911, he married his first wife, Etta Duryea, a Brooklyn socialite who was prone to depression. She committed suicide that same year, after Johnson took up with Lucille Cameron, whose mother so opposed the match that she tried to have him arrested for kidnapping. These charges fell apart when the couple married in December 1911. The U.S. Attorney in Illinois was determined to bring charges against Johnson. After he located Belle Schrieber, Johnson’s mistress in 1910 who had traveled over state lines with the boxer while they conducted their affair, the Mann Act provided a way to do so. The trial opened to international publicity in 1913, and an all-white jury quickly found him guilty of violating the Mann Act. He was to serve one year in jail and pay a $1,000 fine.

Upon sentencing, the judge declared: “The defendant is one of the best-known men of his race, and his example has been far-reaching, and the Court is bound to consider the position he occupied among his people.” To many in America—black and white—Johnson’s conviction was an appropriate measure to restrain a man whose sexual lifestyle struck them as beyond the pale of respectability. Newspaper editorials in the black press celebrated the ruling; the New York Age declared, “There is no reason why we should waste any sentiment upon Johnson.”

Johnson’s prosecution stood out. Most Mann Act cases involved either a commercial element—interstate prostitution—or a very young victim. Johnson’s had neither. Belle Schrieber had sold sex, and Johnson had met her in a brothel, but their relationship was more romantic than commercial. Johnson did give her some of his winnings from the 1910 match to set up a new apartment, and he also loaned her $75 to pay for her train ticket. That loan was enough to convict him.

A flexible racial and gendered double standard was at work. At the age of 26, Schreiber could hardly be classified as a youth, though newspaper coverage of the trial emphasized “girlish qualities” calling her “demure,” “slight” and “rather pretty.” Other cases of white women who had engaged in sex with a black man usually ended with dismissal. Such women forfeited the protection of whiteness. In contrast, the Jack Johnson case was never about vindicating the purity of white womanhood. It always was about punishing a shameless black man for crossing the color line in the bedroom. It was, as the New York Age editorialized, “the apparent hounding and legal persecution” of a celebrity athlete who challenged the racial segregation of America in the most intimate of ways.

At first, Johnson defied the verdict. In a daring escape, he went on the lam. He toured the world, lived in Europe and Mexico and played exhibition matches for income. The aftermath of World War I brought him home. In 1920, the Texas native turned himself in at the U.S.-Mexico border. Johnson served time in Fort Leavenworth, where the prison warden forced him to fight matches eagerly covered by newspapers. The public humiliation of a black man known for his prowess in the ring, his confidence in his black beauty, and shameless pursuit of white women in a Jim Crow world, was complete.

Trump may have acted out of his respect for boxers, concern for men charged with sexual misconduct, or disdain for the FBI, which had jurisdiction over the Mann Act. But whatever his motivations, the pardon opens an opportunity to consider the role that white supremacy has played in the criminal-justice system. Indeed, as the president stated, Johnson “was treated very rough, very tough”; his Mann Act conviction was a “racially motivated injustice.” Setting right a century-old injustice is a first, small step toward addressing the forces of sexual regulation and white supremacy that haunt the past and threaten our present—but preventing future injustices will require a more sustained commitment to reforming America’s criminal-justice system than the president has yet demonstrated.

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