The organized-crime syndicate in the United States is a product of the prohibition era of the early 20th cent. The efforts of federal officials to enforce the unpopular Volstead Act (see Volstead, Andrew Joseph) of 1920 generated the growth of highly organized bootlegging rings with nationwide and international contacts. Although loose alliances were joined among such groups as the Al Capone mob of Chicago, the Detroit Purple gang, and the Owney Madden ring of New York City, gang wars and gangland killings were distinctive features of the 1920s. Powerful gangs corrupted local law-enforcement agencies, even gaining access to high-ranking judges and politicians, such as mayors Frank Hague in Jersey City, N.J., and James J. (Jimmy) Walker in New York City.
Ultimately public revulsion, furthered by the Wickersham Commission investigation of 1930 (see Wickersham, George Woodward) as well as by many municipal exposés (such as that of Judge Samuel Seabury in New York City), led to a crackdown on political corruption. After the repeal (1933) of prohibition, surviving organized crime leaders turned to new avenues of profitable crime, such as labor racketeering, gambling, and narcotics traffic.