This document provides an overview of American foreign policy and national defense based on a textbook chapter. It discusses the country's shift from isolationism to internationalism following World War II. It also describes the key government agencies involved in foreign affairs and national security, such as the State Department, Defense Department, CIA, and INS. The chapter outlines America's foreign policy approaches throughout history, including containment of Soviet expansion during the Cold War. Major events that shaped policy are reviewed, like the Truman Doctrine and Cuban Missile Crisis. The roles of diplomacy, intelligence, immigration, and military in pursuing American interests abroad are summarized.