Employing an analytic construct known as a comparative, foreign-policy analysis framework, the author compares substantive changes in U.S. foreign policy and international politics at two crucial junctures in American history: post-WWII period in which the Cold War began altering U.S. foreign policy for the subsequent fifty-years period versus post 9/11 attacks on the U.S. The volume's framework lends itself to a multi-causal view of foreign policy including multiple theories and permits readers to determine what theories best explain changes in U.S. foreign policy. The volume provides a conceptual definition of foreign policy and examines external inputs, societal, governmental and individual and role inputs to U.S. foreign policy. For those interested in a comprehensive analysis of post-9/11 U.S. foreign policy.