in 1912, he was arrested for violating the Mann Act forbidding a person from transporting a woman across state lines for "immoral purposes."
IOW, he was guilty of violating a federal law. But Jack Johnson was mostly guilty of stupidity, having squandered all the money he won as a boxer. The loony bigot scrawling this screed in The Nation belongs at an intersection, holding up a hand-lettered begging sign. Thanks Kaslin.
Last January I listened to a podcast that talked about Jack Johnson for six hours, and left out the politics. What a career that guy had!