Principles in international law arise from a broad range of sources. These include not only treaties and “customary” international law but also decisions of international courts, tribunals, and arbitrators. Meanwhile, the Supreme Court and other federal courts have shaped the application of international law to certain U.S. settings. Below is an outline of key cases in international law with links to the full text of virtually every case, provided free by Justia.
A primary source of international law is custom, which involves the general and actual practice of a principle and general acceptance of it as a legal obligation. Treaties carry equal weight to custom and may lead to the creation of new custom. General principles of law, also known as international common law, form another primary source of international law. Secondary sources include judicial decisions, scholarly writings, declarations, and resolutions.
Hilton v. Guyot 一 The extent to which the law of one nation, as put in force within its territory, shall be allowed to operate within the dominion of another nation depends on the comity of nations. This is the recognition that one nation allows within its territory to the legislative, executive, or judicial acts of another nation, having due regard both to international duty and convenience and to the rights of its own citizens or other parties under the protection of its laws.
The Paquete Habana 一 International law is part of U.S. law and must be ascertained and administered by U.S. courts when questions of right depending on it are presented for their determination. When there is no treaty and no controlling executive or legislative act or judicial decision, resort must be had to the customs and usages of civilized nations.
The S.S. Lotus (France v. Turkey) 一 Far from laying down a general prohibition to the effect that states may not extend the application of their laws and the jurisdiction of their courts to persons, property, and acts outside their territory, international law leaves them in this respect a wide measure of discretion, which is only limited in certain cases by prohibitive rules.
Diversion of Water From the Meuse Case (Netherlands v. Belgium) 一 International courts have some freedom to consider principles of equity as part of international law. When two parties have assumed an identical or reciprocal obligation, a party that is engaged in a continuing non-performance of that obligation should not be permitted to take advantage of a similar non-performance of that obligation by the other party.
Filartiga v. Pena-Irala 一 Deliberate torture perpetrated under color of official authority violates universally accepted norms of the international law of human rights, regardless of the nationality of the parties. (This federal appellate court considered resolutions and declarations as evidence of customary international law.)
States are the main entities in the international system. In general, an entity is a state when it has a defined territory, a permanent population, an effective government, and international capacity. One theory of state creation is constitutive, which means that the act of recognition confers international personality on the entity. The other theory is the declaratory theory, which suggests that recognition merely acknowledges the existence of facts creating a state.
Corfu Channel Case (United Kingdom v. Albania) (Alvarez opinion) 一 Sovereignty is no longer an absolute and individual right of every state. Instead, the sovereignty of states has become an institution, or an international social function of a psychological character, which needs to be exercised in accordance with the new international law.
Reference re Secession of Quebec 一 A right to secession only arises under the principle of self-determination when a people is governed as part of a colonial empire; when a people is subject to alien subjugation, domination, or exploitation; or possibly when a people is denied any meaningful exercise of its right to self-determination within the state of which it forms a part. In other circumstances, peoples are expected to achieve self-determination within the framework of their existing state.
Island of Palmas Case (U.S. v. Netherlands) 一 The continuous and peaceful display of territorial sovereignty is as good as a title. An inchoate title cannot prevail over a definite title founded on a continuous and peaceful display of sovereignty.
Frontier Dispute Case (Burkina Faso / Mali) 一 The obligation to respect pre-existing international frontiers in the event of a state succession derives from a general rule of international law, whether or not the rule is expressed in the formula uti possidetis.
Case Concerning the Barcelona Traction, Light, and Power Co., Ltd. (Belgium v. Spain) 一 When a state admits foreign investments or foreign nationals into its territory, it is bound to extend to them the protection of the law and assumes obligations concerning the treatment to be afforded them. The government of a state can claim reparation through international judicial proceedings for the damage caused to its nationals by internationally unlawful acts and omissions attributed to another state.
Youmans (U.S.) v. United Mexican States 一 If an official purports to act within their apparent authority, the state is responsible even if the official has exceeded their competence, provided that the act if authorized would be internationally wrongful.
Rainbow Warrior (New Zealand v. France) 一 Distress means a situation of extreme peril in which the organ of the state that adopts that conduct has at that moment no means of saving themselves or persons entrusted to their care other than to act in a manner not in conformity with the requirements of the obligation in question.
The leading intergovernmental organization in the world is the United Nations, which is designed to prevent war and promote human rights, among other goals. The central body of the UN is the General Assembly, while the Security Council is the organ that focuses on matters of international peace and security.
Prosecutor v. Tadic 一 The UN Security Council is empowered and mandated to deal with trans-boundary matters or matters that are domestic in nature but may affect international peace and security. Once the Security Council determines that a particular situation poses a threat to the peace, or that there exists a breach of the peace or an act of aggression, it enjoys a wide margin of discretion in choosing the course of action.
The Law of Treaties
Treaties are binding agreements between subjects of international law that are governed by international law. This means that the parties intend to be bound by international law, and the agreement relates to principles of customary international law. A treaty may simply codify pre-existing custom, or it may address an area lacking in custom or relevant practice.
Advisory Opinion on Reservations to the Convention on Genocide 一 A state that has made and maintained a reservation to a convention to which one or more of the parties to the convention (but not others) have objected may be regarded as being a party to the convention if the reservation is compatible with the object and purpose of the convention. However, if a party to the convention objects to a reservation that it considers to be incompatible with the object and purpose of the convention, that party can consider that the reserving state is not a party to the convention.
Advisory Opinion on Namibia 一 Only a material breach of a treaty justifies termination. Such a breach is defined as a repudiation of the treaty not sanctioned by the Vienna Convention, or the violation of a provision essential to the accomplishment of the object or purpose of the treaty.
Techt v. Hughes 一 Treaties that it is reasonably practicable to execute after the outbreak of hostilities must be observed then as in the past. The belligerents may disregard them only to the extent and for the time required by the necessities of war.
Treaties Under U.S. Law
Treaties made under the authority of the United States are the supreme law of the land. An agreement must be approved by two-thirds of the Senate to be considered a treaty under U.S. law. Some treaties are self-executing, which means that they do not require implementing legislation. A treaty is non-self-executing if it cannot operate without congressional action.
Missouri v. Holland 一 Treaties made under the authority of the United States, along with the Constitution and laws of the United States made in pursuance thereof, are the supreme law of the land.
Reid v. Covert 一 No agreement with a foreign nation can confer on Congress or any other branch of the government power that is free from the restraints of the Constitution.
Medellin v. Texas 一 The President has an array of political and diplomatic means available to enforce international obligations, but unilaterally converting a non-self-executing treaty into a self-executing treaty is not among them. The responsibility for transforming an international obligation arising from a non-self-executing treaty into domestic law falls to Congress.
Foster & Elam v. Neilson 一 A treaty is to be regarded in courts of justice as equivalent to an act of the legislature when it operates without the aid of any legislative provision. However, when the terms of the stipulation import a contract, the legislature must execute the contract before it can become a rule for a court.
Breard v. Greene 一 Although treaties are recognized by the Constitution as the supreme law of the land, that status is no less true of constitutional provisions, to which rules of procedural default apply. If a treaty and a federal statute conflict, the one later in date will control the other.
Murray v. The Charming Betsey 一 An act of Congress ought never to be construed to violate the law of nations if any other possible construction remains.
The Use of Force
Article 2(4) of the UN Charter generally prohibits the threat or use of force by its members against the territorial integrity or political independence of any state. However, Article 51 of the Charter provides a limited exception for self-defense.
Practices that states generally cannot perform or encourage include genocide, slavery, murder, torture, prolonged arbitrary detention, and systematic race discrimination.
Lawless v. Ireland 一 Under the European Convention on Human Rights, the government of any high contracting party has the right to take measures derogating from its obligations under the Convention (with certain exceptions) in case of war or public emergency threatening the life of the nation, provided that these measures are strictly limited to what is required by the exigencies of the situation and do not conflict with other obligations under international law.
International Criminal Law
Crimes that are punishable under international law include crimes against peace, war crimes, and crimes against humanity. The UN Security Council has created temporary tribunals to try individuals accused of crimes related to a specific conflict, such as the breakdown of the former Yugoslavia or the ethnic violence in Rwanda.
Trial of Individuals Before the Nuremberg Military Tribunals 一 A state that holds control over individuals who have violated the laws and customs of war may form tribunals to try these individuals and impose punishment on them. (The Nuremberg Tribunal enforced international law as superior to German law.)
Prosecutor v. Tadic 一 The important consideration in determining whether a tribunal has been established by law is that it be set up by a competent organ in keeping with the relevant legal procedures, and that it observes the requirements of procedural fairness. Also, when an international tribunal is created, it must be endowed with primacy over national courts.
Prosecutor v. Akayesu 一 Rape and sexual violence may constitute genocide in the same way as any other act as long as they were committed with the specific intent to destroy, in whole or in part, a particular group that was targeted as such.
The International Court of Justice
Created by the UN Charter, the most important judicial body in international law is the International Court of Justice, which consists of 15 judges elected by the General Assembly and the Security Council. The ICJ may issue judgments in contentious cases involving states, and it may issue advisory opinions. Its jurisdiction is based on the consent of the parties.
Nuclear Tests Case (Australia v. France) 一 Once the ICJ has found that a state has entered into a commitment concerning its future conduct, it is not the Court’s function to contemplate that it will not comply with it.
Case Concerning U.S. Diplomatic and Consular Staff in Tehran (U.S. v. Iran) 一 A dispute falls within international jurisdiction when it concerns diplomatic and consular premises and the detention of internationally protected persons, and it involves the interpretation or application of multilateral conventions codifying the international law governing diplomatic and consular relations.
Advisory Opinion on Western Sahara 一 The ICJ may give an advisory opinion on any legal question, abstract or otherwise. The fact that it is not the rights of states that are at issue cannot deprive it of a competence expressly conferred on it by its statute.
Traditional theories supporting the jurisdiction of a state include the territorial principle and the nationality principle. More recent, controversial theories include the universality principle and the passive personality principle. States and other international persons may have immunities from the exercise of jurisdiction under international law and sometimes domestic laws.
Blackmer v. U.S. 一 A citizen of the U.S. residing in a foreign country continues to owe allegiance to the U.S. and is bound by its laws made applicable to their situation. One of their duties involves attending U.S. courts to give testimony when properly summoned.
Attorney General v. Eichmann 一 The doctrine of universality of jurisdiction over war crimes provides that every independent state has jurisdiction to punish pirates and war criminals in its custody, regardless of the nationality of the victim or the place where the crime was committed, especially when the criminal otherwise would go unpunished. Also, when the victim of a physical crime is a national of the state that has arrested the culprit, the principle of passive personality may make the “forum patriae victimae” competent to try the case.
U.S. v. Yunis 一 Under the universal principle, states may prescribe and prosecute certain offenses recognized by the community of nations as of universal concern, even without any special connection between the state and the offense. (These crimes include aircraft hijacking, genocide, war crimes, and possibly certain acts of terrorism.) Under the passive personal principle, a state may punish non-nationals for crimes committed against its nationals outside its territory, at least when the state has a particularly strong interest in the crime.
Ex parte Pinochet 一 The international law prohibiting torture has the character of jus cogens or a peremptory norm. This jus cogens nature justifies states in taking universal jurisdiction over torture wherever committed, since people who commit these offenses are common enemies of all mankind, and all nations have an equal interest in their apprehension and prosecution. Also, the implementation of a torture regime cannot be a public function giving rise to immunity.
Schooner Exchange v. McFaddon 一 Full and absolute territorial jurisdiction, being alike the attribute of every sovereign and being incapable of conferring extraterritorial power, would not seem to contemplate foreign sovereigns nor their sovereign rights as its objects.
Berizzi Brothers Co. v. SS Pesaro 一 A ship owned and possessed by a foreign government, and operated by it in the carriage of merchandise for hire, is immune from arrest under process based on a libel in rem by a private suitor in a federal district court exercising admiralty jurisdiction.
This outline has been compiled by the Justia team for solely educational purposes and should not be treated as an independent source of legal authority or a summary of the current state of the law. Students should use this outline as a supplement rather than a substitute for course-specific outlines.