In this groundbreaking reflection on America's relationship with war in the modern era, Gregory A. Daddis explores the deep-seated tension between faith in and fear of war that has shaped US grand strategy and helped militarize US foreign policy with great costs at home and abroad. How have Americans conceptualized and understood the "promise and peril" of war since 1945? And how have their ideas and attitudes led to the ever-increasing militarization of US foreign policy since the end of World War II? In a groundbreaking reassessment of the long Cold War era, historian Gregory A. Daddis argues that ever since the Second World War's fateful conclusion, faith in and fear of war became central to Americans' thinking about the world around them. With war pervading nearly all aspects of American society, an interplay between blind faith and existential fear framed US policymaking and grand strategy, often with tragic results. These inherent tensions--an unwavering trust and confidence in war coupled with a fear that nearly all national security threats, foreign or domestic, are existential ones--have shaped Americans' relationship with war that persists to the current day. A sweeping history, Faith and Fear makes a forceful argument by examining the tensions between Americans' overreaching faith in war as a foreign policy tool and their overwhelming fear of war as a destructive force.