National security undeniably occupies a preponderant place in the political, economic and military agenda of every state. Therefore, the State has a fundamental responsibility in the context of its own internal and transnational security. Whatever way the state adopts to protect itself and its citizens, it must be in accordance with an international system. In this sense the state tends to follow a specific model in terms of international relations. In the case of Western societies in general, and more specifically the United States as the iconic model of the Western world, states tend to favor a realistic perspective in terms of national security. But what exactly is the theory of realism in the field of national security? According to Glaser, the realist vision proposes the achievement of the highest quality standards of national security centered on the acquisition of higher degrees of power among the relevant states, triggering the idea of ​​the presence of an anarchic international system. Taking into account that states evaluate their own strengths in order to adopt the most effective strategies to deal with potential threats, Western states understand the advantages of the aforementioned theory. The current threats that the Western world takes into account are composed of local, regional and global threats. It is essential to this document to recognize the extent of all those elements that pose a threat to the West. Among many others are drugs, crime and terrorism, geostrategic players such as the Middle East and Russia, and rising powers such as China. These are complicated models that states must address strategically. Indeed, the security strategy of Western states is framed between the combination of… middle of paper… and power with which powerful states can govern the weak while preserving their status as regional and global hegemony. Finally, the democratic system is incorporated. While objectionable to some people, democracy serves to spread the altruistic and moralistic rhetoric of a free and peaceful world. Furthermore, Western states do not hesitate in the face of the arrival of new powerful nations or the threat of weapons of mass destruction, they constantly monitor their threats and evaluate what is the most accurate strategy to maintain at least the status quo in this regard. Western states need a realist approach to be well prepared to face any threat. In conclusion, all these reasons have been assimilated by Western states in order to restructure strategic doctrines with the aim of countering any possible threat before it emerges...