الخلاصة:
Much research has been done on the inter-influence between the international situation in which the United States lives, and its conduct in both domestic and foreign policies. This dissertation falls into this category of research.
Some critics of the United States' foreign policy, such as Noam Chomsky and Howard Zinn, see that American policy is not primarily determined by the international events, but rather by the lust for power and economic interests. Other justifications such as security and the promotion of freedom in the world are used as a mask behind which these real motives are concealed.
Others, like Hans J Morgentheau and Kenneth Waltz, see that American foreign policy conduct does and should always depart from the circumstances of the international system and the relative position of the United States in it. The degree to which these circumstances affect national security is one of the major considerations on which foreign policy is conducted. That is, a great part of foreign policy is carried out in such a way that would make the world a safe place for the United Sates. To do so, there has to be a picture of the world and its relation to American national security. Therefore, whenever world circumstances change in nature, this picture will change with it. This is the main issue of this research.
This study aims at analyzing the influence of the world circumstances on the development of the concept of national security in the United States throughout three major periods: the isolationist period, from the nineteenth century to World War II; the Cold War era, form the end of World War II to the late 1980's; and the post-Cold War era, from the late 1980's till the recent years.
Throughout the history of the United States' foreign policy, there have been different views about the extent and the way in which international circumstances affected the safety and integrity of the American people and their territory. From the early years following the American Revolution to the 1940's, most Americans saw that the survival of their people and land could only be guaranteed by getting away of the conflicts of the Old World(Europe), on the one hand, and preventing the old colonial powers from reasserting their presence in the Western Hemisphere.(The American Continents). During the Second World War, this idea was affected by circumstances. The fact that the War, a world conflict that took place beyond the Atlantic, directly endangered American national security led to a break with the trust in isolation as an effective tool to ensure national security. After the War, the security of the United States was believed to require an involvement in international affairs and inevitable alliance with other powers to influence the course of events in such a way that would prevent the new danger, Soviet Union, from affecting the United States. After the international threat of the Soviet Union disappeared, a new one came to the surface: this is international terrorism. After its emergence as a major threat, Americans started to believe that their security could only guaranteed if they destroyed the capacity of every enemy that could strike before even this enemy really attempts to threaten the survival of the American people and land.
Thus, every change on the world scene carries with it a new conception of national security. This change in conception, though it can be exaggerated or distorted by foreign policy makers and the media, is mainly based on the evolution of the world around the United States.