It was on the Fourth of July 99 years ago that Jack Johnson, the proud and gritty African-American boxing champion, outraged the world of bigotry by retaining his heavyweight crown against the “Great White Hope,” Jim Jeffries. Riots ensued across the country as racists took to the streets, while black ghettos celebrated the triumph of their own flamboyant champion, the son of former slaves.

This landmark moment in the struggle up from slavery still has not been set right in history. Jack Johnson fearlessly personified a kind of uncivil disobedience — an outspoken contumely toward the nation’s racist taboos. He had a gift for taunting hypocrites from outside the ring and inside, where shouted racist slurs only galvanized his boxing arts. His was an amazing form of resistance when Jim Crow lynchings and pro-white sports reporting were standard Americana.

Johnson paid the price three years later when vindictive authorities twisted the Mann Act’s strictures against prostitution to convict him before an all-white jury for having dared to travel with a white woman across state lines. He did a year in prison.

A sporadic attempt to expunge this shameful blot has occurred over the years and is finally on the brink of success. The Senate approved a resolution urging an official pardon, and the House is expected to follow suit, with President Obama committed to enacting it as an important moment of justice grossly delayed....