Development of the Red Scare
1. World War One - Increased nationalistic feeling and xenophobia, creating a culture of perceiving immigrants as a threat
2. The Russian Revolution of 1917 - Bolshevik party's communist takeover, concerns about the spread of communism, fears that immigrants intended to overthrow the government
3. Labour strikes - Post-World War One economic slump, increased tensions between employers and trade unions, viewed as examples of political radicalism
4. Anarchist violence - Fear of anarchists, President William McKinley's assassination