THEORY AND PRACTICAL MECHANISMS OF SECURITY GUARANTEES

Abstract

This article examines the problem of security guarantees within the contemporary international order, with a particular focus on the case of Ukraine amid the ongoing Russian–Ukrainian war. Security guarantees are understood as formal and informal commitments designed to reduce existential risks for states in an anarchic international system. The study situates the debate within predominantly realist perspective. Alliance theory helps to highlight how institutions, reputational stakes, and balance-of-threat perceptions can strengthen or weaken guarantees. Evolution of both formal alliances and informal guarantees in a rapidly changing security environment has been assessed. While formal alliances such as NATO provide structured commitments, they remain contingent on political will and are challenged by collective-action problems and asymmetric burden-sharing. Informal guarantees offer flexibility but lack the deterrent clarity of treaty-based arrangements. These dynamics have become increasingly pronounced in an era of intensified great-power rivalry, diffusion of threats beyond conventional warfare, and growing reluctance of states to extend binding security guarantees. The Ukrainian case exemplifies these dilemmas.