According to Christopher D. O'Sullivan, there is still much to consider regarding Franklin D. Roosevelt's foreign policy. Exploring the worldview of Sumner Welles, who became one of Roosevelt's chief foreign policy advisors until Welles's tragic and scandalous resignation in the fall of 1943, O'Sullivan portrays an official coldly hostile to all European powers-allies and enemies alike. Welles resolved to create a postwar global Pax Americana based on the model of the Monroe Doctrine. Using a wide range of primary sources-many of them not previously available-O'Sullivan brings to light the...