J. Edgar Hoover
The Justice Department
Hoover worked at the Library of Congress for five years while attending night school at George Washington University. He received a law degree in 1916 and went on to earn a master's degree in law before passing the bar exam (a test to determine suitability to practice law in a state) in 1917. In July of that year, three months after the United States entered World War I (1914–18), Hoover obtained a draft-exempt position with the Alien Enemy Bureau of the Department of Justice (DOJ). The DOJ would be his only employer in a Washington career exceeding fifty-five years.
With many of America's youth at war, the DOJ was understaffed and Hoover's rise was rapid. He was placed in charge of a unit in the Enemy Alien Registration Section and by 1919 was appointed chief of the new General Intelligence Division (GID). He was special assistant to attorney general and presidential hopeful A. Mitchell Palmer (1872–1936). At the age of twenty-four, Hoover was given responsibility for directing a newly formed section to gather evidence on revolutionary and politically radical groups.
Earlier, while working at the Library of Congress, Hoover had mastered the Dewey decimal system (a numbering system for cataloguing library books) with its classifications and numbered subdivisions. Hoover decided to use that system as a model to create a massive card index of people with radical political views. Over time 450,000 names were indexed. Detailed biographical notes were written on the 60,000 he considered the most dangerous.
From these lists Hoover directed the arrests of suspected radical communists who were caught in the dragnet of the so-called "Palmer Raids" (raids in over thirty cities on aliens known or suspected of being political radicals resulting in thousands of arrests; see sidebar). From the court records in subsequent trials, Hoover also added to his files the names of hundreds of lawyers who had been willing to represent radicals.
His firsthand investigation of American and foreign communists, along with the intelligence files he began gathering, made him the government's first expert on domestic communism.
The Palmer Raids had the desired effect of reducing membership of the American Communist Party. Hoover was rewarded by being promoted to the post of assistant director of the Bureau of Investigation (BOI) in 1921. At that time the BOI employed mostly law school graduates and accountants and had limited power in law enforcement. The agency's main function was to investigate criminal violations of federal law.