While Vollmer and Wilson were laying out the professional model of policing, crime control became the central concern of law enforcement.
The Red Scare
The Red Scare of 1919–1920 consisted of the federal government's, state governments', and vigilantes' suppressing of dissent by radical and left‐wing groups. It reached a climax with the Palmer raids in January 1920. U.S. Attorney General A. Mitchell Palmer orchestrated a series of raids that produced thousands of arrests in 33 cities. The Bureau of Investigation, a federal agency established in 1908, compiled a list of subversives prior to the raids and fostered the fiction that citizens who dissented from government policies were disloyal.
Riots and police racism
More than 20 race riots broke out in the summer of 1919. Studies of these riots reveal discriminatory law enforcement and police participation in the riots.
Expansion of the federal role in law enforcement
Passage of the Harrison Act (1914) and the Volstead Act (1919) expanded the scope of federal jurisdiction over criminal activity. The Harrison Act required physicians marketing drugs to register with the government and pay taxes. To enforce the federal government's first drug law, Congress created the Drug Enforcement Administration. The Volstead Act banned the manufacture, distribution, and sale of alcoholic beverages. To enforce the dry law, Congress established the Bureau of Prohibition (which was a forerunner of the Bureau of Alcohol, Tobacco, and Firearms, a branch of the Treasury Department). Both drug prohibition laws had the unintended consequences of providing an impetus for the growth of organized crime and causing epidemics of police corruption. Pressure on the police to do something to enforce these unpopular, unenforceable laws encouraged the police to violate the civil liberties of many citizens.
J. Edgar Hoover and the Federal Bureau of Investigation (FBI)
J. Edgar Hoover, who served as FBI director from 1924–1972, was the most famous and controversial figure to appear in 20th‐century law enforcement. During the 1930s, Hoover's FBI agents tracked down and captured such gangsters as “Baby Face” Nelson, John Dillinger, “Pretty Boy” Floyd, “Ma” Barker, and the bank robbers/murderers Bonnie Parker and Clyde Barrow. Under Hoover's direction, the FBI became a standard‐setter for law enforcement in the U.S. and the leading example of police professionalism. Hoover's idea of police professionalism included an emphasis on efficient crime‐fighting, police training, scientific crime detection (for example, fingerprinting and lie detecting), a stress on firearms, an authoritarian style of management, and a cynical attitude toward the Constitution in which police officers were to avoid violating citizens' rights not because it was the right thing to do, but because it might result in the loss of a case on appeal. This evangelist for crime control eventually went too far when he attempted to repress political dissent during the Vietnam War and the struggle for civil rights in the 1960s.
Technological and administrative changes
During the 1900s, automobiles, telephones, and radios all enhanced the crime‐fighting capabilities of the American police. Police agencies converted from foot to motorized patrol, allowed citizens' telephone calls for assistance to drive police activities, and used the radio to tighten up monitoring of officers on the streets. Some of these technological innovations had unintended effects on the police. For example, the patrol car removed the officer from the street and reduced police‐citizen contacts, isolating the police from the communities they were responsible for policing.