What is International Law

In most contexts when people speak of the law, they are speaking of the laws of a specific nation. International law is instead the body of laws, rules, and customs that relate to the interaction of different nation states and governments, as well as the international activities of businesses and organizations. International law can be predicated upon custom, treaties and accords, the rulings of international organizations and bodies, and similar sources.

As there is no world government or legislature, it can often be difficult to determine the parameters of international law, what the specific rules are or when and how they should be applied, particularly in the absence of a governing treaty or accord. International law is broken into three broad categories, public international law, private international law, and supranational law.

Public International Law

Public international law relates to nation states, and their relative rights and obligations to each other, as well as to the subjects and citizens of nations. Public international control can be enforced through organizations such as the United Nations or the International Criminal Court.

Public international law relies heavily upon the willingness of nations to voluntarily hold themselves to its standards or, in the event of violation, for other nations to take action to compel compliance. Membership in international organizations is voluntary and in many cases it is difficult for members to compel action or compliance by member states. Public international law arises from:

  • Treaties - Formal agreements between states.

  • Custom - Traditional practices and norms of states, followed to the degree that nations would regard a departure from those norms to be unlawful.

  • Natural Law - General principles of law and conceptions of natural law, common to the world's legal systems.

  • Judicial Decisions - Although the decisions of international organizations are often non-precedential in nature, even when that is the case the opinions of judges and arbitrators can help clarify the rules, boundaries and norms of international law.

  • Legal Scholarship - While scholarly works are not binding on nations, as with judicial decisions they can help clarify customs and norms, or suggest how international law should be applied in specific contexts.

Areas of International Law

Public international law includes:

  • Human Rights Law - The body of international law addressing the inalienable rights of all members of the human family.

  • The Laws of War - Also known as international humanitarian law, the body of law relating to armed conflicts between states, or between states and groups or individuals. International humanitarian law relates both to when war can lawfully be waged, as well as how nations are expected to conduct themselves during an armed conflict.

  • International Environmental Law - Enforcement of international law and agreements relating to the environment, including management of the ocean and fisheries in international waters.

  • Diplomatic Law - The law concerning diplomatic practices, the rights of diplomats and their staffs when present on official duty in another nation state, and the sovereignty of embassies and consulates.

  • International Criminal Law - The enforcement of criminal law for crimes that occur across international boundaries, as well as the enforcement of international criminal law that occurs within a nation state, such as genocide, war crimes and crimes against humanity, piracy and terrorism.

  • International Security - The law pertaining to collective security measures involving military and non-military activities directed against security threats.

Enforcement of International Law

When international law flows from a treaty or compact, the document will usually include provisions relating to enforcement, such as provisions for the arbitration of disputes, or the submission of disputes to the International Court of Justice. A key element of international law is the willingness of nations to voluntarily follow the law.

To a significant degree, compliance flows from reciprocity: the fact that observances and violations of international law are likely to be met with a response in kind. For example, when a violation of a trade agreement is alleged, a state will think twice before imposing tariffs on imported goods out of recognition that the other nation will likely respond by imposing tariffs of its own. When nations are in conflict, they may eject the other nation's diplomats, but will hesitate at taking action against embassies or consulates or mistreating diplomats out of recognition that those actions would put their own diplomats and embassies at risk.

One of the issues that can arise in public international law is that there can be a context in which the law is clearly being violated but no action is taken by the world community in response to the violation, or where the response is so muted that it has no impact on the violation. For example, it has been argued that in the absence of a champion, many groups that are subject to oppression are left without recourse under international law.

Still, when the international community is willing to act against a violation of international law it can resort to a range of actions, ranging from what might be described as shaming or condemnation, to collective actions such as economic sanctions or blockades, to stronger collective actions such as military action.

Private International Law

Private international law relates to the relative rights and responsibilities of private persons and entities when they act across international boundaries. The primary questions addressed by public international law are:

  • Jurisdiction: What nation should have jurisdiction to hear and resolve a conflict between the parties; and

  • Choice of Law: What nation's laws should be applied when evaluating and resolving the dispute.

The world's governments have made efforts to facilitate the resolution of international disputes between private parties, by encouraging the development of guides, model laws and rules, and similar instruments that can help provide guidance to private parties and courts. Nations have also negotiated treaties, conventions and trade pacts that can affect where and how a dispute between private parties is heard and decided.

Supranational International Law

Supranational international law involves the creation of an international organization that transcends the boundaries of nation states, and which is vested with legal or decision-making power in relation to its member states.

Examples of supranational organizations include the World Trade Organization and the European Union. The United Nations Security Council, along with its subordinate organizations such as the International Court of Justice, is the only supranational organization that claims universal jurisdiction.

Copyright © 2014 Aaron Larson, All rights reserved. No portion of this article may be reproduced without the express written permission of the copyright holder. If you use a quotation, excerpt or paraphrase of this article, except as otherwise authorized in writing by the author of the article you must cite this article as a source for your work and include a link back to the original article from any online materials that incorporate or are derived from the content of this article.

This article was last reviewed or amended on May 8, 2018.