A person doing research in our domestic common law system normally employs some or all of the following sources of law:
As primary sources:
Constitutions;
Statutes (codes, compilations, session laws);
Administrative regulations;
Judicial decisions ("court reports");
Administrative agency decisions;
and as secondary sources:
Legal treatises, periodical articles, annotations, looseleaf services, etc.
Such is not the case with International Law research where a researcher will use:
As primary sources:
Treaties, conventions, and the like;
International custom ("customary law");
General principles of law recognized by civilized nations;
and as subsidiary sources:
Judicial decisions;
Legal treatises, periodical articles, and the like (known as "the teachings of the most highly qualified publicists").
(Resolutions and declarations of international organizations: Some nations advance the view that Resolutions and Declarations of international bodies, the United Nations in particular, ought to be accepted as sources of international law rules. The matter is disputed, and the United States does not accept this point of view.
It is clear, then, that a search for "The Law" in international legal research will turn to sources quite different from those normally used in Anglo-American law studies. The process of using treaties and international conventions (agreements) should not occasion much difficulty, because treaties are usually published by the governments involved, are usually available to researchers in law libraries, and are relatively specific in language. Because the drafting of treaties is roughly similar to the drafting of statutes, treaties are often referred to as "international legislation". Keep in mind, however, there is no such thing as a legislature with international jurisdiction ... not even the United Nations. SEE: Any Pathfinders on TREATIES.
The difficulty may come in determining what "customary law" is. International customary law is made up of two elements: (1) a certain procedure, rule, pattern of behavior, or conduct carried out over a period of time (not specified), and (2) an agreement (explicit or tacit) by nations that this procedure or conduct is obligatory as law. In short, a pattern of behavior without more is not sufficient to create a customary rule of international law.
One may also experience some difficulty in determining the content of "general principles of law recognized by civilized nations", but the concept is fairly simple. An example of a such a principle would be the Anglo-American rule of res judicata; that is, once you've had your day in court and have exhausted your appeals, you cannot raise the matter again at a later time. No matter what they call it, virtually all civilized nations follow such a rule or practice in their court systems. International lawyers would view this rule as "a general principle of law recognized by civilized nations", a principle that could also be applied in appropriate cases involving questions of international law.
A researcher who needs to ascertain (1) customary rules of international law, or (2) general principles of law recognized by civilized nations would likely start his/her research in relevant texts and treatises, law review articles, judicial decisions (both those of national courts and those stemming from international tribunals), and even statements made in landmark resolutions and declarations of the United Nations. The on-line catalog and the card catalog are excellent places to begin, as are the various periodical indexes. Because international legal matters are frequently litigated in American courts, particularly in the federal courts, one should also check through the usual federal digests, state digests, and legal encyclopedias like Corpus Juris Secundum (CJS) and American Jurisprudence, 2d (AmJur2d). SEE: Any appropriate Pathfinders for these research tools (Digests or Encyclopedias)
See discussion above, immediately before TREATIES. Although most nations do not accept resolutions and declarations per se as sources of international law rules, a resolution or declaration may restate well established rules of international law. In that case, the resolution or declaration is simply a statement (or "restatement") of international law. Moreoever, a resolution or declaration may become a rule of international law through the development of customary law. If nations follow a practice or rule laid out in a declaration or resolution and gradually begin to accept it as obligatory, then that practice or rule becomes a customary rule of international law (see above for discussion.)
