The week of Christmas 1947: Outside, the record shows, the air was a bracing 38 degrees. Inside the conference room of the U.S. Supreme Court, the temperature was rising. Seven of the nine justices had gathered to resolve a controversy over their law clerks’ desire to sponsor a Christmas party that ultimately will never be held.

Was the source of the controversy religion in an institution sensitized to others’ beliefs by a recent string of Jehovah’s Witnesses cases? Or was race simmering below the surface of the court’s own segregated marble halls?