“International law traditionally flourishes with liberal hegemony, shared interests, or balance-of-powers parity. The first condition is visibly waning. The second and third conditions support regional and functional islands of multilateralism. While those islands may sometimes be shaky, they will continue to provide work for international lawyers.”

Among the most diverse and disparate legal practice areas is the practice of international law.

Although the notion of treaties and trade agreements between countries may first come to mind when one contemplates the field of international law, it is, in fact, much more varied than that. From cross-border intellectual property claims to maritime law, military jurisdictional issues, and child custody disputes, the field is wide open to practitioners possessing assorted backgrounds and areas of expertise. We will examine the opportunities that exist for international lawyer.

Between Nation-states

The first element in determining whether a matter falls within the rubric of international law is the diversity of geography between the parties. This is true whether the parties are nation-states involved in a dispute or even private citizens of different states who need to look to international law to resolve a conflict. The claim at issue may be one of banking, project finance, a trade issue, or an environmental dispute, but once the parties have diversity of nationhood or national citizenship, the claims will likely be litigated under international norms rather than domestic legal ones.

International Commercial Practices

International commercial matters are typically governed by conventions and treaties that have been entered into between two or more states. However, despite the enormous body of such signed Lex Mercatoria agreements, international practitioners also rely upon customs and usages—collectively, ‘Customary Law’—that have evolved over the centuries regarding global commercial transactions. In May 1969, those customs were codified in the Vienna Convention on the Law of Treaties by the International Law Commission of the United Nations, which went into effect on January 27, 1980.

Because such practice is international in scope, American lawyers who practice international commercial law might be posted to an overseas office of a multi-national corporation, the foreign offices of a U.S. law firm, or be assigned to the offices of an international organization overseeing trade, intellectual property, maritime, or import-export customs issues. They may also be assigned to a U.S. consulate or embassy.

Public Versus Private International Law

Aside from legal topics of dispute, the practice of international law is further broken down into two different categories: ‘public international law’ and ‘private international law’, the former involving nation-states as the parties and the latter involving private entities engaged in cross-border disputes. An example of an international public dispute would be a grievance involving economic law, diplomatic law, or human rights law, whereas an example of a private international dispute would be liability claims arising from the release of toxic substances, such as the Chernobyl nuclear plant meltdown or the gas leak in Bhopal, India.

Practice Before Tribunals

Perhaps one of the best-known international law tribunals is the International Court of Justice (ICJ), which is the judicial arm of the United Nations. UN member states have assigned jurisdiction to the ICJ to settle legal disputes between nations; however, the UN itself is yet another international body before which international law practitioners appear to argue their clients’ claims during UN commission and committee sessions.

The International Criminal Court (ICC) investigates cases in which genocide, war crimes, and other ‘crimes against humanity’ have been alleged and, in some circumstances, conducts trials of the accused. It is considered complementary to, and not a replacement of, national courts. Not all UN member states bring cases to the ICC, and its jurisdiction is limited to those states that are signatories to the Rome Statute.

Interpol—the international criminal police organization—is yet another international body where international law practitioners might file requests for arrest warrants to be issued or to contest warrants that interfere with their client’s freedom of movement. And the Court of International Trade, a U.S. tribunal, has jurisdiction over civil actions arising from federal laws governing import transactions.

International Environmental Law

In recent years, concern over protecting the environment and mitigating climate change have spurred both interest and participation in global environmental law forums and regulatory bodies. The Stockholm Declaration of 1972 resulted from the United Nations Conference on the Human Environment, and practitioners also monitor the progress of the United Nations Environment Program.

A key element of international environmental law is achieving cooperation between sovereign states and among the industrial players operating within their borders. Principle 21 of the declaration provides that a state must prevent activities in its territory that harm the environment of other states. A decade after the declaration was signed, the World Commission on Environment and Development introduced the concept of sustainable development, allowing states to meet their present needs without preventing future generations from being able to meet theirs. Achieving that delicate balance has also fallen under the purview of international law practitioners.

Cross-border Family Law

Although domestic child custody disputes are addressed by state and federal law, when international child custody disputes arise, the applicable jurisdiction and law may be difficult to determine. Nevertheless, The Hague Convention—an international treaty—has sought to clarify and universalize which laws apply in such circumstances. The Hague Convention may be useful in returning a child who has been wrongfully removed to another country; however, as with the Rome Statute referred to above, the Hague Convention only applies to those countries which are signatories to it.

In sum, no one area of practice comes under the heading of “international law,” and lawyers looking to enter this field may very well find their experience and expertise in a wide variety of practice areas suitable in the international law arena.

Executive Summary

The Issue

What areas of practice fall under the heading ‘International Law’?

The Gravamen

A wide range of practice areas encompass international law, comprised of civil disputes, criminal matters, disputes between nation-states, and disputes between citizens of different geographical locations.

The Path Forward

In order to determine whether an international law case exists, first examine the issue of the international diversity of the parties.


1. Signatory Status:

A thorough examination should be made in order to discover whether a particular convention or treaty has been entered into that governs your international law issue.

2. Customary Law:

Even if a specific convention or treaty does not govern in your case, research whether or not customs and usages apply, and if so, whether they have been codified.

3. Applicable Tribunal:

A myriad of tribunals exist governing everything from trade to maritime law, the environment, and child custody; determine before which tribunal your dispute may be heard.

4. Private International Law:

International claims and not only among nation-states, and your private clients may also have claims for which knowledge of international law may become crucial.

Further Reading:


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