May 1938. Franklin Delano Roosevelt--recently reelected to a second term as president--sat in the Oval Office and contemplated two possibilities: the rule of fascism overseas, and a third term. With Hitler's reach extending into Austria, and with the atrocities of World War I still fresh in the American memory, Roosevelt faced the question that would prove one of the most defining in American history: whether to once again go to war in Europe. In...