6. Law, Politics, and the Use of Force
This chapter explores the role of international law in international politics, with particular emphasis on the effectiveness of legal constraint of the use of force by states. It first considers the effect of international law on state behaviour, focusing on the so-called ‘perception–reality gap’, before discussing three reasons why states obey the law: coercion, self-interest, and legitimacy. It then examines the concepts of jus ad bellum and jus in bello; the former governs and seeks to limit resort to armed force in the conduct of international relations, while the latter governs and seeks to moderate the actual conduct of hostilities. Jus in bello is further subdivided into Geneva law and Hague law, both of which generally have the status of jus cogens.