THE American Mafia emerged during Prohibition as the wealthier and more violent successor to local city gangs involved in prostitution and gambling. It is thus a contemporary of the Soviet Union, another long-standing problem for the United States government. Coincidentally, the Mafia and Soviet Union have ceased to be significant strategic adversaries at almost the same time. The Mafia is almost extinguished now as a major actor in the United States’ criminal world. And, to extend the comparison with the Soviet Union perhaps beyond its fair limits, the Mafia’s decline is the result of both its conservatism and of federal government actions.