Is Foreign Law International Law?
An Associated Press news release dated October 18, 2005, begins with the headline, "Gonzales Weighs in on International Law." The news release, with the headline, was picked up by several newspapers, including the Los Angeles Times, the Washington Post and the Baltimore Sun. The body of the article discussed Attorney General Alberto Gonzales' view, expressed in a speech at George Mason University, that the U.S. Supreme Court should not consider foreign law in making its decisions.
Foreign law is not the same as international law. Foreign law is the law of an individual foreign country or, in some instances, of an identifiable group of foreign countries that have a common legal system or a common set of rules in a particular field of law. From the United States' perspective, European Union law or the law of the European Convention for the Protection of Human Rights and Fundamental Freedoms would be in the latter category.
International law is the law in force between or among nation-states that have expressly or tacitly consented to be bound by it. Its primary sources are treaties to which specific countries are parties (binding upon those countries, but not upon other countries) and custom. Customary international law stems from the practice of international entities (primarily national governments) over some period of time that has hardened into a reasonably firm expectation that the practice will govern future conduct by all countries that have not clearly objected to the practice during its gestation. A customary rule could develop out of a treaty rule if the treaty rule is widely enough recognized, in which case it could bind countries that are not parties to the treaty. Conversely, an unwritten customary rule may ultimately be codified in the form of a treaty, as has happened, for example, with respect to large segments of the law of the sea.
Long ago the United States Supreme Court said, "International law is part of our law, and must be ascertained and administered by the courts of justice of appropriate jurisdiction, as often as questions of right depending on it are duly presented for determination." Exactly what that means is open to debate, but it clearly holds the door open to the use of international law by US courts, including the Supreme Court, in some cases. Attorney General Gonzales addressed a different question: whether the US Supreme Court should look to foreign law for guidance regarding norms applicable to legal issues that have arisen both in the United States and in foreign countries. What he said has no bearing on the use by American courts of international law norms to which the United States has expressly or tacitly consented.
About the author
Frederic L. Kirgis, an ASIL member, is Law Alumni Association Professor of Law Emeritus at Washington and Lee University. He has written books and articles on international law, and is an honorary editor of the American Journal of International Law.
 See the United Nations Convention on the Law of the Sea, UN Doc. A/CONF.62/122 (1982), 1833 UN Treaty Series 3.
 The Paquete Habana, 175 US 677, 20 S.Ct. 290 (1900).
 There is a body of US case law, still being developed in the courts, that deals with the application of international law norms in US courts. The issues raised by those cases are too complicated to go into here. But those issues are distinct from the question of using foreign law to supply guidance for decisions in US courts.