Find out each Man's Thumbscrew. ’Tis the art of setting their wills in action. It needs more skill than resolution. You must know where to get at any one. Every volition has a special motive which varies according to taste. All men are idolaters, some of fame, others of self-interest, most of pleasure. Skill consists in knowing these idols in order to bring them into play.
Knowing any man's mainspring of motive you have as it were the key to his will. Have resort to primary motors, which are not always the highest but more often the lowest part of his nature: there are more dispositions badly organised than well. First guess a man's ruling passion, appeal to it by a word, set it in motion by temptation, and you will infallibly give checkmate to his freedom of will.
Baltasar Gracian - The Art of Worldly Wisdom (1647)
Does Cameron keep his hand in his pocket these days? I must check.