The Palmer Raids were significant in U.S. history as a key episode in the Red Scare following World War I. Initiated in 1919 and led by U.S. Attorney General A. Mitchell Palmer, these raids aimed to deport suspected radicals and anarchists amid fears of communism spreading in America. The raids led to thousands of arrests, many without proper warrants or just cause, and often involved brutal treatment. They reflected the tension between national security concerns and civil liberties, highlighting issues of governmental overreach. The Palmer Raids ultimately stirred public debate over immigration policy and civil rights, influencing later 20th-century attitudes toward dissent.