There were conflicting accounts of what happened on that bus. Joyous soldiers, black and white, may have been sharing a celebratory bottle of whiskey. Woodard and the driver argued about restroom breaks and Greyhound’s rules requiring a driver to accommodate passengers’s needs.

When the bus stopped in Batesburg, a small town about 30 miles from Columbia, the state capital, the driver summoned the town’s two police officers, Chief Lynwood Shull and his deputy, Elliot Long, and Woodard was ordered off the bus.

Shull admitted using his blackjack on the sergeant. When Woodard wrested it away, Long, gun drawn, ordered him to drop it. Then, by the Gergel book’s account, Shull rained blows on Woodard so ferociously the blackjack broke. Woodard was left sightless, both eyes gouged out, and thrown in jail, igniting a racial fuse that would burn its way across America to Waring, the White House and eventually the Supreme Court.

“It’s more than just an incident, it’s a huge historical moment,” said Patricia Sullivan, a professor of history at the University of South Carolina and author of “Lift Every Voice: The NAACP and the Making of the Civil Rights Movement.”

As a law student at Duke University in the 1970s, Gergel had read of Waring. But passing mention of Woodard escaped him and he didn’t think much of Waring again until, as an intellectual property and personal injury lawyer and outside counsel to the city of Columbia, he was named to the federal bench.

“In my installation talk, I spoke about Judge Waring,” Gergel recalled. “I saw blank looks.”

He plunged into research, using his inside knowledge of court dockets and evidentiary records. “I understood what I was looking at,” he said. “I knew what to ask for.”