I'll address the Red Scare of the 1920s, since it was the one that involved the most change. After Russia fell to the Bolsheviks in 1917-1918, America was afraid that Russian agents would seek to use labor unrest in order to topple the government. A. Mitchell Palmer, Postmaster General under Woodrow Wilson and Attorney General under the Harding administration, began to round up anyone whom he thought was a Communist sympathizer. This was a main reason that Progressive issues left the national political landscape--people were worried about anything that looked like too much government involvement in the private sector. Palmer deported many suspected radicals whose only offense was having Eastern European or Jewish origins. Politically, the U.S. put quotas on European immigration, limiting Eastern European immigration to a trickle at a time when millions of deserving refugees wanted to flee the Soviet Union. Socially, it became popular to criticize leftist ideas as being "un-American." Even though due process was not followed through with the deportations of suspected radicals, Americans began to look at recent immigrants from Eastern Europe suspiciously. Labor union membership also dropped, and business began to actively ask government to get back to the laissez-faire practices of the late 1800s, which it soon adopted.