In the 1920s and 1930s Jewish gangsters united to form large-scale businesses that dealt in prostitution, extortion, drugs and bootlegging. They also went into the assassination business to ensure that they remained in power throughout the major cities of the United States. Some Jewish gangsters united with their Italian contemporaries and functioned under Mafia rules. By the Second World War, battles over turf and arrests by the Federal Bureau of Investigation had convinced many of these people to go legitimate and they moved to Las Vegas and went into the entertainment business.
What is interesting is that some of the Jewish mobsters, such as David Berman, fought valiantly during the war or supported the Allied effort in other ways such as protecting the docks and ports where they remained in power.