What events in Europe led some Americans to fear foreigners and foreigners and foreign ideas after World War 1?

After World War I, a wave of anti-foreign sentiment in the United States was fueled by several events in Europe, including the Russian Revolution of 1917, which brought Bolshevism into the spotlight and stoked fears of communism. Additionally, the rise of nationalist movements and widespread labor strikes in Europe contributed to anxieties about radical ideologies infiltrating American society. The influx of immigrants from war-torn Europe also heightened concerns about cultural differences and economic competition, leading to a general climate of suspicion and xenophobia in the U.S. during the 1920s.