•A foreign policy geared towards pursuing the national interest is the foundation of the realist school of international relations.
•The realist school reached its greatest heights at the Congress of Vienna with the practice of the balance of powers, which amounted to balancing the national interest of several great and lesser powers.
•These notions became much criticized after the bloody debacle of the First World War, and some sought to replace the concept of the balance of power with the idea of collective security (idealism)
Whereby all members of the League of Nations would “consider an attack upon one as an attack upon all,” thus deterring the use of violence forevermore.
•League of Nations did not work, partially because the United States refused to join and partially because, in practice, nations did not always find it “in the national interest” to deter each other from the use of force.
•The events of World War II led to a rebirth of Realist and then Neo-realist thought