b. The Palmer raids
The Palmer Raids (1919-1920) were a series of raids conducted by the U.S. Department of Justice led by Attorney General Mitchell Palmer, to arrest and deport foreign anarchists, communists, and radical leftists.
Palmer focused on foreigners since the Immigration Act of 1918 set that finding a foreigner as a memberof radical organizations was sufficient justification for his/her deportation. This way, the Justice Department was able to deport over 500 number of foreign radicals without the obstacle of a trial.