The Hatch Act of 1939 is a United States federal law whose main provision is to prohibit federal employees (civil servants) from engaging in partisan political activity. Named after Senator Carl Hatch of New Mexico, the law was officially known as An Act to Prevent Pernicious Political Activities.
The act precluded federal employees from membership in "any political organization which advocates the overthrow of our constitutional form of government." During the Second Red Scare, this designation was interpreted to include communist and labor organizations.