As A Soldier’s Play?—?running now at the Shubert Theatre through Dec. 11?—?opens, a group of faceless and as yet nameless soldiers join in a song. Their performance is full of strength, energy, even joy. But the song is a work song, captured at Parchman Farm, the notorious maximum-security Mississippi State Penitentiary, in which inmates were made to work in conditions all too reminiscent of slavery. The parallel is clear these Black soldiers in the U.S. Army, at (the fictional) Fort Neal in Louisiana, deep in the Jim Crow South, are in some sense prisoners...