Introduction: The article examines theoretical and methodological approaches to understanding sovereignty as an integral feature of the state, defined as: sovereignty of the will of the people, acting as the source of state power; sovereignty of the state apparatus of power as the bearer of public power; sovereignty of the territorial organization of public power, ensuring the unity and integrity of the state. The analysis of the legal policy pursued by Russia to ensure sovereignty and national security is carried out. The reasons and stages of legislative regulation in national law of responsibility for crimes of peace and security of mankind are defined. Materials and Methods. In the course of the study were used general scientific and private-scientific methods, which allowed to reveal the theoretical and methodological foundations of understanding the sovereignty of the state, to analyse Russia's legal policy to ensure national security, to determine the causes and stages of legislative regulation in national law of responsibility for crimes against peace and security of mankind. The Results of the Study. The diversity of approaches to the understanding of sovereignty as a feature of the state is revealed. The concept of sovereignty of the will of the people and the state apparatus of power as a source and carrier of state power is considered. The principles of ensuring the sovereignty of the state as a territorial organisation of public power that ensures its unity and integrity are defined. The reasons are outlined and the stages of the legal policy pursued by Russia to ensure sovereignty and national security in the context of ensuring peace and security of mankind are highlighted. Findings and Conclusions. At the current stage of legal regulation, a significant importance is assigned to further improvement of the lawmaking process and development of legal techniques that allow at the legislative level to respond in a timely manner to new challenges caused by a qualitatively new stage in the development of international and interstate relations, associated with the renewal of the world order and posing significant threats to the preservation and maintenance of state sovereignty. The ongoing transformation of international relations, which has led to changes in both the architectonics of the world order and the structure of the world order, has provoked an increase in local conflicts and threats that contribute to the reduction of the level of global and national security. Military-political concepts declared by a number of foreign states confirm their desire to increase the hotbeds of geopolitical conflict. One of the measures of strategic planning is a consistent legal policy of the state on the formation and timely modification of legal means to ensure the sovereignty of the state, peace and security of both individual peoples and states, and humanity as a whole. Countering negative trends associated with the development of neo-Nazism, the rehabilitation of neo-fascism, the propaganda of genocide, extremist ideology, Christianophobia, Islamophobia and anti-Semitism should be recognised as key areas contributing to the solution of contemporary problems in the sphere of ensuring peace and security of mankind.