Defensive Realism and the Logic of NATO's Existence after September 11

Introduction The September 11, 2001 incident has entered NATO in a new phase in its political life. In addition to the various issues, terrorism, expanded the agenda of this security organization and led to a new interpretation of NATO's constitution, especially its fifth article. The theory of realism in the context of a research program and defensive realism as an advance in this program research addresses the expansion of the NATO expansion after 9/11.
Methodology This study, considering the rationalist theory of international relations as an attempt to explain the causes of the events and with applying the theory of defensive realism, has used a descriptive-explanatory method to advance the purpose of the research.
Findings
1. Defensive realism as an advance in realistic research program: Defensive realism by adding complementary propositions to the core of realist research program used this great theory of international relations to explain the specific behaviors of governments and security alliances.
2. September 9, 2001 and Norm-making in International Politics: The September 11, 2001, along with the great effects on great power relations and the redefinition of concepts such as power, preventive and preemptive war, Has led to a review of some international norms such as legitimate defense.
3. Changing concepts in international politics and changing the agenda of security institutions: The dynamics of the events in the international environment, especially in the military – security arena, has led to the redefinition of concepts such as national security and power, which has changed the agenda of security institutions.
4. Defensive realism and the persistence of security allies: This research shows how defensive realism by adding auxiliary propositions to the core of realism, as a research program, explains the process of transforming and changing the principles of international institutions , why international security institutions be continued after Solving it’s the existential threat has been durable question in the literature of realism; defensive realism is trying to answer this question. Analysis This research takes into account NATO developments in its evolution after World War II, Particularly; the changes made to this important security institution after 9/11 And has used the theory of defensive realism as an advance in the research program to explain NATO Developments.
Conclusion The findings of this study show how defensive realism with preserve of realism hard core as the Great Theory of International Politics And only with some adjustments in its protective belt, It can turn into a theory to explain the foreign policy behavior of countries and international security institutions. To prove this claim, based on this theory, NATO's developments after September 9, 2001, have been explained.