What promped the hysteria during the Red Scare?

The hysteria during the Red Scare was primarily prompted by a combination of fear of communism and the influence of radical leftist movements following the Russian Revolution of 1917. Events such as labor strikes, bombings by anarchists, and the establishment of the Soviet Union heightened public anxiety about the spread of communism in the U.S. Additionally, government actions, including the Palmer Raids, fueled fears of internal subversion and led to widespread paranoia, resulting in the persecution of individuals perceived to be associated with leftist ideologies.