As for Eisenhower himself, Welch characterized him, in words that have made the candy manufacturer famous, as “a dedicated, conscious agent of the Communist conspiracy” — a conclusion, he added, “based on an accumulation of detailed evidence so extensive and so palpable that it seems to put this conviction beyond any reasonable doubt.”

Richard Hofstadter (1916-1970) American historian and intellectual

“The Paranoid Style in American Politics,” Herbert Spencer Lecture, Oxford (Nov 1963)
    (Source)

Reprinted in Harpers (Nov 1964).