The evolution of the principle of separation of powers in the public law of foreign countries

The study is dedicated to a comprehensive analysis of the evolution of the principle of separation of powers in the public law of foreign countries, from its ancient origins to the complete concepts of the Enlightenment era. It examines the ideological foundations and prototypes of the separation of powers in the works of ancient Greek thinkers, particularly Plato, who distinguished governmental functions and contemplated mixed forms of government. Special attention is paid to Aristotle, who clearly identified three elements of state structure – the deliberative body, organs of administration, and judicial institutions – emphasizing their importance for the nature of the state. The contribution of Polybius is analyzed, who, using the example of the Roman Republic, described a system of mutual control and counterbalances between the elements of a mixed form of government. Medieval attempts to limit monarchy are explored, such as the dualism of spiritual and secular power , feudal relations , and the adoption of Magna Carta in 1215, which laid the foundation for the rule of law and due process. The role of the formation of estates-general representative bodies (parliaments) as an institutional basis for the future separation of powers is considered. The influence of the Renaissance and Reformation eras is highlighted, including Niccolò Machiavelli’s ideas on the advantages of a mixed form of government, as well as Edward Coke’s contribution to upholding the supremacy of common law and Jean Bodin’s formulation of the concept of state sovereignty with the distinction of legislative, judicial, and executive functions. A central part of the study is the analysis of classical concepts from the Enlightenment: John Locke, who in «Two Treatises of Government» justified the need to limit state power to protect natural rights and distinguished legislative, executive, and federative powers , and Charles Louis Montesquieu, who in «The Spirit of the Laws» detailed the concept of three branches (legislative, executive, judicial) and justified the mechanisms of «checks and balances» as a guarantee of political freedom. Jean-Jacques Rousseau’s concept of popular sovereignty is also analyzed; while criticizing the separation of powers into independent branches, he emphasized its indivisibility and the supremacy of the general will as the source of laws.