The first Red Scare was a period during the early 20th-century history of the United States marked by a widespread fear of far-left movements, including Bolshevism and anarchism, due to real and imagined events; real events included the Russian 1917 October Revolution and anarchist bombings in the U.S. At its height in 1919–1920, concerns over the effects of radical political agitation in American society and the alleged spread of socialism, communism, and anarchism in the American labor movement fueled a general sense of concern.

The Palmer Raids were a series of raids conducted in November 1919 and January 1920 by the United States Department of Justice under the administration of President Woodrow Wilson to capture and arrest suspected socialists, especially anarchists and communists, and deport them from the United States. The raids particularly targeted Italian immigrants and Eastern European Jewish immigrants with alleged leftist ties, with particular focus on Italian anarchists and immigrant leftist labor activists. The raids and arrests occurred under the leadership of Attorney General A. Mitchell Palmer, with 6,000 people arrested across 36 cities. Though 556 foreign citizens were deported, including a number of prominent leftist leaders, Palmer's efforts were largely frustrated by officials at the U.S. Department of Labor, which had authority for deportations and objected to Palmer's methods.