(Commentary by Risa L. Goluboff, dean of the UVA School of Law) In January 1959, Sam Thompson entered the Liberty End Café in Louisville. While he waited to catch a bus nearby, he ordered macaroni and a beer and shuffled his feet to the music. Two police officers entered the bar and arrested Thompson for loitering. In short order, the local police court convicted Thompson, and not for the first time. Thompson had been arrested and convicted of loitering, vagrancy and other petty crimes more than 50 times, in part because he was poor and in part because he was black. Some of the particular...