There is no evidence to support the belief that Soviet Premier Nikita Khrushchev ever questioned Americas power. He questioned only the President's John F. Kennedys readiness to use it. Elie Abel, The Missile Crisis (1966) Power tends to corrupt and absolute power corrupts absolutely.
Letter to Bishop Mandell Creighton, 3 April 1887, in Louise Creighton 'Life and Letters of Mandell Creighton' (1904) vol. 1, ch. 13.