One of the most revelatory anecdotes in William Manchester’s intimate biography of Winston Churchill, The Last Lion, describes his reaction to a complaint by a servant at Chartwell, Churchill’s country estate in Kent, about his employer’s habitual rudeness to him. “But I am a great man,” Churchill expostulates. The instinctiveness of this response, the unaffected astonishment—bordering on innocence—that anybody should question his right to behave exactly as he chose reflects the certainty of position still felt in England in the 1930s by a descendant of the great Duke of Marlborough and cousin of the incumbent at Blenheim Palace. This in…