"Law Abiding Citizen," a blunt and sadistic revenge thriller starring Jamie Foxx and Gerard Butler, occasionally pauses from the mayhem to stage a solemn debate about law, justice and morality. Mr. Butler, playing a family man whose wife and daughter were murdered by thugs, feels he was let down by the system, which gave one of the thugs a light sentence in exchange for testimony against the other thug, who was sentenced to death. Mr. Foxx, the prosecutor who made that deal, thinks that the system, however imperfect, did its job. More >>