the McCarran Internal Security Act of 1950. Is anyone willing and able to explain the significance of this act of Congress, including its intent and purpose, and how the law was widely considered to be a violation of civil liberties?

Answer 1

http://www.google.com/search?rlz=1C1GGGE_enUS379US379&aq=f&sourceid=chrome&ie=UTF-8&q=McCarran+Internal+Security+Act+of+1950

The Wikipedia article will give you the best explanation.

You might also look up this: House Committee on Un-American Activities