McCarthyism is a term used in reference to accusations of disloyalty, subversion or treason, without due respect to a fair legal process where the rights of the accused are respected.
It originates in an episode in the history of the United States that took place between 1950 and 1956 during which Senator Joseph McCarthy (1908-1957) unleashed an extended process of statements, unfounded accusations, denunciations, interrogations, irregular processes and blacklists against people suspected of being communists.