But there was an earlier Red Scare, which combined a fear of anarchy and communism with a fear of foreign influence--and eventually expanded to include virtually all progressive activism. During the late 1910s, American intervention in World War I provoked a massive internationalist antiwar movement that created American liberalism as we know it today.
As liberalism expanded and became more cosmopolitan, conservatism contracted and became more nativist. Anti-German sentiment led the most professedly patriotic Americans to refer to sauerkraut as "liberty cabbage" and, occasionally, to do much more--as when German immigrant Robert Praeger was wrapped in an American flag and lynched by a crowd of angry "unhyphenated Americans." Soon it became illegal to speak German, Russian, and other foreign languages in some cities and states, more than 16,000 people were arrested and imprisoned without trial for alleged communist sympathies during the infamous Palmer Raids, the government-endorsed American Protective League encouraged private citizens to spy on foreign or suspiciously freethinking neighbors, and the Sedition Act of 1918 made it a crime to say anything "disloyal, profane, scurrilous, or abusive" about the U.S. government or its policies.
When five-time American Socialist Party presidential candidate Eugene V. Debs was imprisoned under the Act for speaking out against World War I, it gained him 900,000 votes in the 1920 presidential election--even though he was serving what would become a life-shattering sentence in Atlanta Federal Prison at the time.
Where was the U.S. Supreme Court? Squarely on the side of the establishment. In Schenck v. United States (1919), the Supreme Court held, astonishingly, that the Sedition Act was constitutional.
America needed the ACLU.