I have long been settled in my own opinion that neither Philosophy, nor Religion, nor Morality, nor Wisdom, nor Interest, will ever govern nations or Parties, against their vanity, their Pride, their Resentment, or Revenge, or their Avarice, or Ambition. Nothing but Force and Power and Strength can restrain them.

The Adams-Jefferson letters (ed. The University of North Carolina Press, 1988)