The Role of NATO and the European Union in Transforming the European Security System in the Context of the Russia-Ukraine War

This paper presents a comprehensive analysis of how Russia's large-scale war against Ukraine on February 24, 2022, changed the European security architecture and the impact of the conflict on the policies of the main security actors in Europe – NATO and the European Union. The relevance of the issue is due to the impact of the war's consequences on European security. The conflict led to a political, humanitarian and energy crisis in Europe, which forced the European Union, NATO and individual European countries to reconsider their foreign policy strategies, defense and security policies and relations with Russia. Analyzing the transformation of the strategies of the European Union and NATO allows us to determine the interaction of the two organizations, differences in approaches and prospects for transforming the common security system. The aim of the study is to analyze the role of the European Union and NATO in the development of the European security system, to determine the institutional and political dynamics of their strategies, and to study key challenges and trends. The following tasks are set within the framework of the work: to analyze the transformation of the European security system after the Russian invasion of Ukraine; to study the impact of the conflict on the activities of NATO and the European Union and the national security of European countries; to study the prospects for future integration and defense mechanisms in Europe. The results of the study show that Russia's war against Ukraine led to the strengthening of military-political cooperation between NATO allies, an increase in defense spending in EU member states, further rapprochement between NATO and the EU to ensure common transatlantic security, and a significant diversification of Europe's energy sector. The paper uses comparative research methods, case studies, political and legal analysis, as well as content analysis of statements by political leaders and international organizations and official strategic documents.