This article presents the issues of legitimacy, particularly concerning the global reality of the institution of power in the context of present-day conditions of international politics, with particular emphasis on fragile states functioning mainly in the area of the contemporary “Third World”. The legality and legitimacy of power analyzed here undoubtedly have significant implications for the internal politics of fragile states, regional good neighborly relations, and international politics, particularly in the context of the global security strategy. This article examines the above issues primarily in the context of policy theory. As a result, several research questions arise: to what extent and how does legitimacy affect the effectiveness of the political strategies used by the authorities? Are other factors and stimulators of political commitment also taken into account? What is the importance of legitimacy in the context of the complex conditions of the politically and economically ineffective fragile state? Is legitimacy, apart from the moral and ideological dimension, significant in the destabilized reality of the weak political and economic structures of a failing state? The analysis, in this way, makes it possible to interpret and present many important factors for which the concept of the legitimacy of power plays a significant role in reflecting on the geopolitical determinants of fragile states in contemporary international relations.