All revenge films are, by their very nature and aesthetics, law films. What is socially unacceptable becomes cinematically irresistible. Moviegoers do not reject celebrations of vengeance by walking out of theaters and demanding their money back. Quite the opposite: The injustice on screen provides the moral justification for the protagonist to settle the score on his or her own terms. Meanwhile, audiences remain glued to their seats. No one moves until the wrongdoer receives what he deserves. To do otherwise, to allow the wayward to get away with it, would be morally unbearable.

The only requirement that gives the revenge film its moral authority to take such liberties with the social contract is the law’s failure to do the right thing. Once the law fails, the avenger is instinctively catapulted into action, as if deputized by the law’s absence. Failure can take many forms. There are procedural foul-ups that set murderers free in such films as In the Bedroom, Eye for an Eye, The Shawshank Redemption and The Brave One. There are corrupt sovereigns, judges, prosecutors and law enforcers in films such as Sweeney Todd, Gladiator, Braveheart, Ragtime (and its debt to Michael Kohlhaas), and the granddaddy of all revenge movies, The Count of Monte Cristo. The avenger might be trying to send the system a message about its own cynicism and complicity. Law-Abiding Citizen, Runaway Jury and Sleepers come to mind. In Westerns, the wild and wide-open prairies do not allow for the procedural niceties of insular courtroom dramas. What are required in such moments of rough justice are posses, pistols and nooses. The Searchers, Unforgiven and, of course, True Grit are the classics of this category.

There are, to be sure, other subgenres about the law. Horror films, for instance, are essentially movies about the law. A truth is buried (even if a body isn’t), a murder goes unpunished, and the knowledge of “what someone did last summer” must see daylight—even if it requires the dead, coming out at night, to haunt the living to bring it about.

Quiz: Which movie lawyer are you?