Muhammad Ali's Greatest Fight October 5, 8 p.m., HBO.

Despite its title, the HBO original movie Muhammad Ali’s Greatest Fight isn’t really about Muhammad Ali. The legendary boxer appears only in archival footage, while the central narrative focuses on the nine Supreme Court justices who decided his fate in 1971. That’s when Ali’s appeal of his draft-dodging conviction reached the nation’s highest judicial body, and the movie spends most of its time behind the scenes as the justices deliberate Ali’s case (along with brief looks at other cases of the same session, related to anti-war protests and employment discrimination).

Director Stephen Frears (The Queen) assembles an impressive lineup of actors to play the justices, including Christopher Plummer, Frank Langella, Danny Glover and Ed Begley Jr., but they’re more historical mouthpieces than fully fleshed-out characters. Plummer’s John Marshall Harlan II gets most of the focus, as it was his vote that ultimately decided the Ali case, but other than a few touching moments with his wife and some heavy-handed depictions of his declining health, he serves mainly to articulate legal arguments. Even worse, the filmmakers invent a clerk (played by Benjamin Walker) who ends up heavily influencing Harlan’s opinion, and who exists solely to state the movie’s point of view.

When the real-life footage of Ali’s speeches and interviews is consistently more fascinating than the scripted drama, it’s clear that the movie’s priorities are off. The copious exposition that sounds awkward coming from the mouths of actors playing characters would have fit much better in a documentary; maybe HBO can commission one of those instead.