Immaterial. Communism is a philosophy of economics. It is not a government or governing philosophy. That said, communism is a system of economics in which the means of production is run by the proletariat, not strongmen or individuals. It is HIGHLY unlikely communism could ever work or even be attempted in it's pure form beyond a group of about 150 individuals, as it would require immense trust and personal relationships.
No major industrial nation has implemented pure communism. They all implement heavily modified forms (much like most nations implement highly modified forms of capitalism, as pure capitalism would very quickly lead to revolution once a nation passed a certain point in its economic development).
Churchill, McCarthy, and the rest used Communism as shorthand for the Soviet Union, which was Stalinist at that time.