Who was A. Mitchell Palmer? What groups of people did he target for deportation from the United States? Why were these groups of people targeted?

A. Mitchell Palmer was a former U.S. Attorney General who rounded up thousands of people that he believed were part of a Bolshevik conspiracy to overthrow the federal government.
Alexander Mitchell Palmer was a lawyer, Congressman from Pennsylvania and the U.S. Attorney General under President Wilson (1919 – 1921).
Using the Espionage Act of 1917 and the Sedition Act of 1918, Palmer launched a campaign against political radicals, suspected dissidents, left wing groups and aliens.
In January 1920, federal agents in thirty-three cities captured thousands during the infamous “Palmer raids”. Palmer was discredited for ignoring civil liberties as the agents held people for extended periods of time without formally charging them.
He believed that the raids were justified as the only practical way to fight a Bolshevik conspiracy to overthrow the federal government.
Encyclopædia Britannica Online, s. v. “A. Mitchell Palmer”, accessed December 30, 2015, http://www.britannica.com/biography/A-Mitchell-Palmer.