This book examines the impact of the National Security Act of 1947, the most important foreign policy legislation that many Americans (including policymakers and academics) have never heard of.

Since September 11, 2001, the White House—under both Bush and Obama—has pushed the envelope of taking the United States to war (without declarations), interrogating prisoners of war, spying on potential threats, and acting unilaterally. Why have these trends occurred? How has the apex of foreign power shifted, causing a sea change that has fueled a continual turf war between Capitol Hill...