Final answer:
The Red Scare was fueled by fears of a communist revolution similar to Russia's, leading to heightened nativism and suspicion towards immigrants. Events like the discovery of letter bombs and the Palmer Raids escalated the fear and suppression of perceived radicals, but as threats failed to materialize, public skepticism grew and the fervor receded.
Step-by-step explanation:
The climate of fear during the Red Scare in the United States was the result of a convergence of political, social, and psychological factors in the wake of World War I. Politically, the Bolshevik Revolution in Russia sparked a global fear of a wave of communism that could potentially spread to other nations, including the U.S. Socially, the country experienced a surge in nativism, with a pronounced fear of immigrants, particularly those from Eastern Europe, who were often suspected of carrying socialist or anarchist ideologies. The discovery of letter bombs addressed to prominent figures only intensified this fear. Psychologically, such incidents exacerbated an already-tense atmosphere, leading to a nationwide panic and witch-hunt for communists and their sympathizers. Acts like the Palmer Raids demonstrated the extent to which the government would go to quash perceived threats to American democracy, often at the expense of civil liberties. The subsequent backlash against A. Mitchell Palmer and his aggressive tactics illustrated the dynamic tension between national security and individual rights during this period. As fear subsided, however, the public began to view such actions with skepticism, contributing to an eventual decline in the hysteria associated with the Red Scare.