 The focus of this entry is on developments that have occurred since World War II. In the aftermath of World War II, an unprecedentedly sophisticated international architecture of legal norms and institutions, to a large extent associated with the United Nations system, was established. With the end of the Cold War, and the spread of globalization, this architecture reached new heights of ambition, claiming authority over a diverse range of governmental matters that were formerly treated as falling within the exclusive province of state authority. The scope of international law expanded to cover new subject-matter, such as the relationship between the individual and the State, migration, or the environment. Many now perceive the “international rule-based order” to be imperilled by the rise of authoritarian powers, on the one hand, and of populist forces in the Western world, on the other; both are said to be hostile to international law, especially to certain aspects of it like human rights (Alston 2017; Ginsburg 2020; Neuman 2020; Wuerth 2017). For others, the expansion of international law poses a challenge to the liberal foundations of domestic sovereignty. This entry is inevitably selective, focusing on some general conceptual and normative questions, but discussions of the discrete domains of international law can be found elsewhere in the Stanford Encyclopedia (see e.g., the entry on  human rights).