Collective security mechanism as a model for maintaining and expanding international security requirements, and coordinate, which has been criticized by neo-realists for its idealistic nature. On the other hand, violating this mechanism directly or indirectly affects the function of the collective security model. Throughout history, the US as a supreme power has played an important role in weakening or strengthening the collective security model. Presidents of this country after World War II And based on Truman's doctrine with an internationalist approach, they have been able to define a specific role for the United States in the international security mechanism in their national security doctrine. The forty-fifth president of America Donald Trump, who has considered foreign policy, Has made a mistake In the perspective of the role played by the United States since 1945 with an internationalist approach before the Trump in the international system. America's foreign policy during the presidency of Donald Trump which is rooted in nationalist views, by emphasis on national interests of the United States And with an economics-oriented approach As well as the impact of some of its institutionalized foreign policy features, including unilateralism, Intentionally or unintentionally weaken the collective security. Eventually, this trend intensifies because of the increasing self-sufficiency of governments Will lead to an increase in the anarchy of the international system.