There are few things quite like a mass arrest to serve as a reminder of the Mafia's continuing presence in American life. The mob roundup last Thursday morning, the largest in U.S. history, at once underscores the large dent that the Justice Department has been making in organized crime and how entrenched many of their operations have been. Some 800 FBI agents, U.S. marshals, state police and New York City cops fanned out and arrested nearly 120 wise guys and associates named in an 82-page, 16-count indictment for acts of murder, racketeering, money-laundering, loan-sharking, extortion and other offenses...