Jump to Content Jump to Main Navigation

III Custom as a Source of International Law

From: The Sources of International Law (2nd Edition)

Hugh Thirlway

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2023. All Rights Reserved.date: 22 September 2023

Customary international law

This chapter considers the question of whether custom is a source of international law. It discusses the constituent elements of custom, changes in customary law, the relevance of ethical and similar principles to customary law, and the extent of application of a rule of customary international law. In treating custom as a source of legal rules, international law does not deviate from the pattern discernible in municipal legal systems. Historically, at the international level, once the authority of natural law, in the sense of what was given by God or imposed by the nature of an international society made up of independent princes, had weakened, it was natural to derive legal obligations from the legitimate expectations created in others by conduct. However, the precise nature and operation of the process have always presented obscurities.

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.