Dr. Siddik ARSLAN
Volume: 14 Issue: 04, 2026
Abstract:
This study examines, from an interdisciplinary perspective, the impact of the separation of powers on states’ foreign policy processes and their position in international relations. Systematized by Montesquieu, this principle constitutes one of the fundamental pillars of democratic governance by ensuring a balanced distribution of power among the legislative, executive, and judicial branches. Rather than treating the principle solely as a matter of constitutional law, the study evaluates it within the framework of comparative foreign policy analysis and international relations theory. By bringing together democratic peace theory, liberal institutionalism, and structural realism, it addresses the multidimensional role of the separation of powers within a holistic framework. Adopting a comparative method, the research examines established democracies such as the United States, Germany, and France alongside states with different forms of government such as Türkiye, China, and Russia through qualitative analysis, document examination, and case studies. The findings show that where the separation of powers operates robustly, foreign policy is conducted more consistently, predictably, and transparently. In these states, legislative oversight and judicial independence anchor foreign policy decisions within a legal framework, strengthening compliance with international law, adherence to agreements, and diplomatic credibility. This outcome rests on the fact that subjecting foreign policy decisions to multi-institutional approval and to scrutiny makes the commitments given more binding and more credible. Conversely, in authoritarian and hybrid regimes where the principle is weak, decisions are taken by a narrow circle, generating unpredictability and distrust in the international arena. The study further shows that states grounded in the separation of powers assume more constructive roles in international organizations, manage crises more successfully, contribute more effectively to global governance, and, through the rule of law, offer a stable environment for investors. The separation of powers thus emerges as a structural variable shaping not only domestic governance but also states’ effectiveness, credibility, and legitimacy in the international system.