Shocked by the fall of France in 1940, panicked US leaders rushed to back the Vichy government-a fateful decision that nearly destroyed the Anglo-American alliance. According to US Secretary of War Henry Stimson, the "most shocking single event" of World War II was not the Japanese attack on Pearl Harbor, but rather the fall of France in spring 1940. Michael Neiberg offers a dramatic history of the American response-a policy marked by panic and moral ineptitude, which placed the United States in league with fascism and nearly ruined the alliance with Britain. The successful Nazi invasion of France destabilized American planners' strategic assumptions. At home, the result was huge increases in defense spending, the advent of peacetime military conscription, and domestic spying to weed out potential fifth columnists. Abroad, the United States decided to work with Vichy France despite its pro-Nazi tendencies. The US-Vichy partnership, intended to buy...