American foreign policy is the subject of extensive debate. Many look to domestic factors as the driving forces of bad policies. Benjamin Miller instead seeks to account for changes in US international strategy by developing a theory of grand strategy that captures the key security approaches available to US decision-makers in times of war and peace. Grand Strategy from Truman to Trump makes a crucial contribution to our understanding of competing grand strategies that accounts for objectives and means of security policy. Miller puts forward a model that is widely applicable, based on empirical evidence from post-WWII to today, and shows that external factors—rather than internal concerns—are the most determinative.