Explanatory of stability and Enlargement of NATO from the prospective of Threat Balance TheoryStephan Walt's

With the collapse and disintegration of the Soviet Union, it was expecting that the North Atlantic Treaty Organization (NATO) was completely eliminated as a Cold War institution. But unlike the organizations and institutions such asthe Warsaw Pact, not only NATO was not dissolved, But prepared itself for new tasks in the post-Cold War period and the collapse of the Soviet Union. The fact that why despite removing the risk of communism and the loss of formation philosophy, the North Atlantic Treaty Organization did not face with the risk of dissolution and collapse, and even began its development and expansion? The researchers of the present paper seek to answer with an explanative method. Therefore, the theory of this paper claims that in the perceptions of NATO leaders, though great danger was erased by the Soviet Union collapsed, But the re-empowerment of the Russians, the instability caused by the change in the political systems of formerly communist countries, the danger of terrorism, and governments and groups equipped with weapons of mass destruction were threats that could challenge the international order and security of the post-war world. Therefore, maintaining NATO's military organization in order to counteract with these threats became to irrefutable necessity for NATO leaders.