On June 18, 1940, Churchill delivered his celebrated “Finest Hour” speech. The British army had been evacuated from Dunkirk. France, under Pétain, had decided to surrender. “Hitler knows that he will have to break us in this island or lose the war,” Churchill told the House of Commons. “If we can stand up to him, all Europe may be free and the life of the world may move forward into broad, sunlit uplands. But if we fail, then the whole world, including the United States, including all that we have known and cared for, will sink into the abyss of a new Dark Age made more sinister, and perhaps more protracted, by the lights of perverted science.” Two of those phrases — “broad, sunlit uplands” and “the abyss of a new Dark Age” — should ring in our ears as we approach the end of this hinge year in history. Broad, sunlit uplands are the women of Iran tearing off their hijabs the way the people of Berlin once tore down their wall. And Ukrainian soldiers raising their flag over Irpin, Lyma...