Published online by Cambridge University Press: 05 June 2012
Since I wrote my initial essay on national security for this volume more than a decade ago, the concept's utility for studying American foreign policy has grown. Its attractiveness stems from its synthetic qualities; its synthetic qualities stem from the fact that it is not a specific interpretation that focuses on a particular variable as much as a comprehensive framework that relates variables to one another and allows for diverse interpretations in particular periods and contexts.
National security policy encompasses the decisions and actions deemed imperative to protect domestic core values from external threats. This definition is important because it underscores the relation of the international environment to the internal situation in the United States and accentuates the importance of people's ideas and perceptions in constructing the nature of external dangers as well as the meaning of national identity and vital interests.
By encouraging students of American foreign policy to examine both the foreign and the domestic factors shaping policy, by obligating them to look at the structure of the international system as well as the domestic ideas and interests shaping policy, the national security approach seeks to overcome some of the great divides in the study of American diplomatic history. Heretofore, the most influential studies of American diplomatic history have stressed the moralistic or legalistic or idealistic strains in American foreign policy, or, alternatively, the quest for territorial expansion and commercial empire and geopolitical influence.