Forty years ago, an important emissary was sent to France by a beleaguered president of the United States . It was during the Cuban missile crisis and the emissary was a tough-minded former secretary of state, Dean Acheson. His mission was to brief French President Charles de Gaulle and solicit his support in what could become a nuclear war involving not just the United States and the Soviet Union but the entire NATO alliance and the Warsaw Pact. At the end of the briefing, Acheson said to de Gaulle, "I would now like to show you the evidence, the photographs...