Without on-screen assurance that most of this courtroom farce's dialogue was drawn verbatim from court transcripts, you'd dismiss its vaudeville antics as sheer baloney. Veteran director Sidney Lumet's shambling spectacle, based on the 1987-88 trial of 20 members of the New Jersey branch of the Lucchese crime family, is certainly evidence that truth is stranger than fiction, but it's also tedious and shockingly uninvolving. Its center is the larger-than-life "Jackie Dee" DeNorscio (Vin Diesel), a wisecracking Lucchese wiseguy and midlevel racketeer with his finger in a bakery's worth of illegal pies. Jackie is lewd, crude and uneducated, but he loves his family — his daughter, the ex-wife who left him because of his relentless womanizing, his aging parents and even the junkie cousin (Raul Esparza) who shot him four times. And Jackie loves his guys — he's been in and out of jail most of his life and never, ever ratted them out, not even after the ambitious prosecutor (Linus Roache) who engineered his entrapment on a narcotics charge promises a reduced sentence in exchange for damning information on his associates. Jackie goes to trial with 19 of his oldest pals — a trial that lasts close to two years — and, serving as his own lawyer, uses the legal proceedings as a platform for his earthy humor and deeply held views on honor and loyalty. It's hard to pinpoint where this film goes so terribly wrong: Lumet has made great movies about the legal process (12 ANGRY MEN, THE VERDICT), petty crooks who are more complicated than they first appear (DOG DAY AFTERNOON), and men torn between fealty to friends and personal ethics (SERPICO); maybe he was defeated by the sheer volume of characters or the fact that Jackie was pure "what you see is what you get." Diesel — transformed by a false head of thinning hair and facial prosthetics — doesn't radiate the overwhelming charisma that would offset Jackie's fundamental loathsomeness, but his performance is thoroughly respectable. Maybe there's just not much left to say about the Mafia in a post-GODFATHER, post-GODFELLAS, post-Sopranos world; whatever the reason, the film is dreary and attenuated, the tedium broken only by the occasional golden moment when one of the stellar supporting players — Ron Silver as the principled presiding judge who alternately tolerates and quashes Jackie's antics, Peter Dinklage as the lead defense attorney or Annabella Sciorra as Jackie's ex — manages to cut through the clutter.