A new HBO movie about Muhammad Ali's legal battle against the military draft sheds rare cinematic light on the inner workings of the Supreme Court.

Muhammad Ali’s Greatest Fight, set to debut on October 5, shows justices in 1971 scheming and lobbying each other over Ali's case, with Justice John Harlan II — played by Christopher Plummer — making a last-minute switch that had the effect of keeping Ali out of jail and allowing him to resume his legendary boxing career.