On Nov. 7, 1919 Jan. 2, 1920, the Justice Department launched two waves of mass arrests.  Over 4,000 suspected Communists radicals were arrested many were forced to leave the United States.
      On April 15, 1920, Sacco Vanzetti were arrested on the charge of involvement in a murder robbery case. They were convicted sentenced to death. But there was little evidence to prove they were guilty. Strong, wide-spread protests did not save them. They were executed in 1927. People said they died for their radicalism. 
 (The example of Ku Klux Klan can also be used.)