The Red Scare of 1919-1920 was the first, but not the last, widespread outbreak of anti-communist sentiment in U.S. history. In a national panic over alleged foreign-inspired subversion, people of varying political beliefs were termed "Reds" and became victims of public rage and government suppression. The culmination of these events was the arrest and deportation of hundreds of American citizens—particularly immigrants—in the Palmer Raids of 1920.

The event that initiated the Red Scare was the Bolshevik Revolution of November 1917 in Russia. Inspired by the writings of German philosopher Karl Marx, the Bolsheviks, under the leadership of Vladimir Lenin, believed that the revolution in Russia was the first in a chain of workers' revolutions that would spread throughout the world. In March 1919, the Bolsheviks founded the Communist International to coordinate communist parties worldwide and promote revolution abroad. Many Americans became fearful that, just as a...