Excerpts from Books and Wikipedia
"In 1953, McCarthy became the chairman of the permanent subcommittee on investigations and used the position to press the 'comsymp' witch hunt forward. Some of his suspicions were more securely founded than his critics cared to admit, but he and his committee's chief counsel, the New York lawyer Roy Cohn, had no regard for evidence and ruthlessly destroyed the reputation of innocent people. To what extent McCarthy believed in his crusade or understood the harm he was doing to his country is still disputed." [Furtado: 1001 Days]