Thomas E. Dewey

Dewey left Wall Street in 1931 to become the youngest person to hold the title of chief assistant U.S. attorney for the Southern District of New York. It was the oldest and largest of the nation's ninety-four legal divisions. Dewey temporarily became U.S. attorney in November 1933 until Democratic president Franklin Roosevelt (1892–1945; served 1933–45) filled the post a month later. During his years in the department, Dewey actively prosecuted New York's most powerful organized crime figures.

In the early 1930s, violence in the criminal underworld was increasing as new, younger leaders were challenging the authority of the older gangsters. The outlawing of liquor, called Prohibition, in the 1920s had opened up the profitable business of bootlegging (selling illegal liquor), which led to the dramatic growth of organized crime. With the end of Prohibition in 1933, competition over control of other potentially lucrative illegal activities grew intense. These activities included loan-sharking, stolen goods, and narcotics, among others. The media was filled daily with reports of bloody battles between crime families.

New York City mayor Fiorello La Guardia (1882–1947), newly elected in 1934, was determined to rid the city of gangsters. La Guardia instructed Dewey to investigate "Dutch Schultz," whose real name was Arthur Flegenheimer. Police believed Schultz was behind a large number of crimes, but Schultz was murdered in a gangland slaying before Dewey could bring him to trial.

Dewey obtained seventy-two convictions out of the seventy-three prosecutions of leading criminals during his years as Special Prosecutor. Dewey's greatest success came when he obtained a conviction against Charles "Lucky" Luciano, in 1936. Luciano was New York's most notorious Mafia figure. By 1937 Dewey's fame had spread and he was elected district attorney of New York County.