Communism is an ideology, with roots in the writings of Karl Marx, that aims to establish future classless and stateless social organisations based upon common ownership of the means of production and the absence of property. It was the attempts of political regimes in the twentieth centuries to put the communist ideology into practise that most contributed to the view held by many that it is a negative thing. Communist regimes in Stalin's Soviet Union, Mao's China and Pol Pot's Cambodia were responsible for millions of deaths - through direct murder or via famine brought about by their economic policies - and for other human rights abuses and limitations on freedom such as that imposed by rigid censorship The Cold War between the communist Soviet Union and its Eastern Bloc satellite states and the U.S and the West added to the fear and suspicion in which communism was held, a notable manifestation of which were the Senator McCarthy-led anti-communist witch-hunts in 1950s America.
