The Red Scare following World War 1 was caused primarily by?

The Red Scare following World War I was primarily caused by widespread fear of communism and radical leftist ideologies, particularly in the wake of the Russian Revolution of 1917. This fear was exacerbated by labor strikes, social unrest, and the perceived threat of anarchist and socialist movements within the United States. Additionally, the rise of immigrant populations, often associated with radical political beliefs, fueled paranoia and suspicion, leading to government crackdowns and societal backlash against perceived subversives.