Throughout his life, Churchill held remarkably modern, enlightened views. Many prominent figures throughout history—including the Founding Fathers—did. Enlightened views possess universality, by definition of Enlightenment.
Churchill remained consistent in his views throughout his life. This consistency is typical of great men. They perfect their views all while betting that their time will come instead of scheming how to best take advantage of prevailing political fashions.
Churchill respected tradition but challenged norms. This quality would have helped him in American politics, had he been born there.
Churchill's privileged upbringing prepared him well to thrive on adversity. Perhaps the same upbringing has also taught him what kind of adversity the British people were willing to endure and what kind they would have had none of. Only a great man can live with the enormous responsibility of choosing action over inaction: of sending his people to fight in a world war instead of surrendering. A defining feature of greatness is the willingness to accept responsibility.