President Harry S. Truman signed United States Executive Order 9835, sometimes known as the "Loyalty Order", on March 21, 1947. The order established the first general loyalty program in the United States, designed to root out communist influence in the U.S. federal government. Truman aimed to rally public opinion behind his Cold War policies with investigations conducted under its authority. He also hoped to quiet right-wing critics who accused Democrats of being soft on communism. At the same time, he advised the Loyalty Review Board to limit the role of the Federal Bureau of Investigation to avoid a witch hunt. The program investigated over 3 million government employees, just over 300 of whom were dismissed as security risks.
The Loyalty Order was part of the prelude to the rise of Senator Joseph McCarthy, Republican of Wisconsin. It was mostly the result of increasing U.S.–Soviet tensions and political maneuvering by the president and Congress. The order established a wide area for the departmental loyalty boards to conduct loyalty screenings of federal employees and job applicants. It allowed the United States Federal Bureau of Investigation to run initial name checks on federal employees and authorized further field investigations if the initial inquiry uncovered information that cast someone in a negative light. Executive Order 9835 also was the main impetus for the creation of the Attorney General's List of Subversive Organizations (AGLOSO).
As U.S. relations with the Soviet Union rapidly deteriorated following World War II, there were accompanying concerns about government infiltration by communists. As the U.S. fell from being wartime allies to staunch adversaries with the USSR, American obsession with perceived dangers associated with the Soviet Union, and Communists in general, began to grow. Much of this obsession was fueled by reports, in and out of the government, of Soviet spy activity in North America. Economic tension helped foster a general state of anger and anxiety in the United States and its government. As Congressional elections approached in late 1946, many American conservative groups attempted to ignite a new Red Scare. The Republican Party, assisted by a coalition that included the Catholic Church, the FBI and private entrepreneurs, worked to inflame public fear and suspicion. As fear of Communist infiltration in the government grew, it became a central campaign issue in the 1946 elections.