Echoes of modern controversies could be heard Wednesday night in the U.S. Supreme Court chamber.

“The Muslim faith is not a pacifist faith,” one lawyer said. Another countered that Muslim doctrine does not require the faithful to “pick up a gun in any war.”

But the debate was not a rehearsal of litigation over the Trump administration's travel ban, or any other current headline-making case.

Instead, it was a “re-enactment” of the 1971 Supreme Court case Clay v. United States, in which legendary boxer Muhammad Ali appealed the rejection of his application for conscientious objector status at the height of the Vietnam War.

Sitting at the chief justice's center chair, Justice Sonia Sotomayor presided over the mock hearing sponsored by the Supreme Court Historical Society. Ali's widow Lonnie Ali and other family members attended too. Justice Clarence Thomas, who sometimes seems bored on the bench, watched raptly from a spectator's seat.

Veteran New York litigator Theodore Wells Jr. of Paul, Weiss, Rifkind, Wharton & Garrison argued on behalf of Ali, and when it was over, he tucked two quill pens—they are handed out to court advocates—into his breast pocket. The late civil rights lawyer Chauncey Eskridge argued for Ali in 1971.

Representing the government in opposition to Ali was Jones Day partner Donald Ayer, channeling long-ago Jones Day partner Erwin Griswold, who argued the Ali case in 1971 as U.S. solicitor general. A former deputy solicitor general himself, Ayer wore the traditional morning coat for the occasion.

Setting the stage for the event was former law school dean Thomas Krattenmaker, who clerked for Justice John Harlan II the year the Ali case was decided. Both Krattenmaker and Harlan played key roles in the “sub rosa” deliberation after the oral argument that turned a loss into a win for Ali, as Krattenmaker described it. Those behind-the-scenes maneuvers, recounted in a 2013 HBO movie, overshadowed the argument itself.

But Sotomayor made it lively nonetheless. Wells started out by requesting four minutes of rebuttal time, which high court practitioners don't ask for so explicitly. “Three,” Sotomayor shot back.

Considerable time was spent on the belligerence—or lack thereof—of the Muslim faith. A key issue in the Clay case was whether he and his religion eschew all wars, or just some wars—a factor used in granting or denying conscientious objector status. Ali's own statements about war were ambiguous.

Once the argument was over, Sotomayor amused the audience when she said, “Remind me if I ever have to sit in this chair again, I need to have it raised.” She recounted how the eight-member court—Thurgood Marshall was recused because of his involvement in the case as solicitor general—was ready to vote against Ali until Harlan, who was assigned to write the opinion, changed his mind. Krattenmaker had given Harlan a copy of Elijah Muhammad's “Message to the Blackman in America,” a book that convinced him that Muslims in general, and Ali in particular, were for all practical purposes opposed to all war.

Harlan's colleagues were not happy with his change of mind. “If anyone did that today, wow!” Sotomayor exclaimed. But Harlan's shift got other justices thinking about a compromise. In the end, the court issued a per curiam opinion that sidestepped controversial issues but ruled for Ali on grounds that the government was unclear about why he was denied objector status.

Describing Ali as “quite the poet,” Sotomayor tried her hand at poetry too in handing down the opinion Wednesday night. “We granted cert on a narrow question presented,” she said. “But now the government says, 'We never meant it.'” She finished by saying, “Mr. Ali, you're free. We reverse.”