The twenty-first century has witnessed significant challenges to the traditional view that international humanitarian law exclusively regulates the use of force in armed conflict. The death and destruction caused on September 11,2001, reflect the increasingly complex nature of modern conflict. Groups that rely on the benefits of globalization and technological advances to conduct operations across international borders are threatening the maintenance of international order. Their tools of violence range from conventional weapons of war to more modern weapons of mass destruction and potentially asymmetric “cyber attacks.”

Among “jurisconsults of recognized competence in international law” and “most highly qualified publicists of the various nations,” no one in the second half of the twentieth century did more than Oscar Schachter to influence both the theory and the practice of international law, especially the law of the United Nations Charter. When the centennial of the American Society of International Law arrives in two years, we will have occasion to reflect on his contributions to this Journal and many other endeavors of the Society, across a long and vigorous life.

On the docket of the United States Supreme Court in 2004 is a substantial cluster of cases at the intersection of constitutional and international law. In the previous two Supreme Court Terms, the Court had adverted to sources of law and practice outside the United States, in its treatment of constitutional claims involving the death penalty and same-sex relationships. The apparent willingness of the Court to consider international and foreign authorities in reaching its conclusions on contested issues of constitutional law has raised to new promir nence the debate over the relationship between constitutional and international law. It is not yet clear whether the new (or newly rediscovered) interest of the Court in international sources presages a long-term trend toward a more cosmopolitan constitutional jurisprudence. On the assumption that this represents more than a passing fad, advocates before the Court in die current Term—for example, in the cases involving die “enemy combatant” detainees at Guantanamo Bay—have vigorously pressed arguments concerning international and foreign law in connection with the constitutional issues at stake. The Court's acceptance of quite a few cases raising a mixture of international and constitutional questions for decision in 2004 may signal that the Court is preparing for a new era of engagement with legal developments external to the United States, or, alternatively, that it seeks to limit (or in any event to delimit) the relevance of such developments for the U.S. legal system.

What did the United States Supreme Court mean when it famously 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 upon it are duly presented for their determination”? Perhaps the Court was suggesting that, in an interdependent world, United States courts should not decide cases without paying “a decent respect to the opinions of mankind,” in the memorable words of the Declaration of Independence. The framers and early Justices understood that the global legitimacy of a fledgling nation crucially depended upon the compatibility of its domestic law with the rules of the international system within which it sought acceptance. Their recognition seems both prudent and sensible. Even today, for any nation consciously to ignore global standards not only would ensure constant frictions with the rest of the world, but also would diminish that nation's ability to invoke those international rules that served its own national purposes.

In the keynote address to the 2003 annual meeting of the American Society of International Law, Justice Stephen Breyer declared that “comparative analysis emphatically is relevant to the task of interpreting constitutions and enforcing human rights.” Justice Breyer concluded that nothing could be “more exciting for an academic, practitioner, or judge than the global legal enterprise that is now upon us.” In a room filled with international lawyers and academics, he received a home court standing ovation.

In two recent cases—Atkins v. Virginia and Lawrence v. Texas—amicus briefs urged the U.S. Supreme Court to use international materials to expand the scope of domestic constitutional rights. In a footnote in Atkins and three paragraphs in Lawrence, the Court may have signaled a willingness to listen. Some applaud the beginning of a positive trend. Others—notably Justice Antonin Scalia in dissent in the two cases—condemn the entire project as illegitimate.

Rather than seeking an immediate answer to the question whether international materials should be determinative of domestic rights, this essay makes an indirect approach by asking: if we are to undertake a serious project of using international materials in this way, what would that project look like? Identifying the nature of the project may suggest whether it is the sort of thing we want to undertake, and what the scope of its impact is likely to be.

Is international law “irrelevant” to constitutional interpretation in the United States? How could that be? The arguments for categorical ignorance of international law in constitutional adjudication play on exaggerated fears: fear of foreign domination, fear of judicial activism, fear of the unknown. The claim of irrelevance depends on a false dichotomy between excluding international law fromjudicial consideration and allowing foreign institutions to control constitutional meaning. The more sensible inquiry would ask how international law has informed constitutional interpretation in the past, and how it should be used in the future.

The preceding contributions to this Agora investigate the discernible trend in Supreme Court decisions of citing international legal materials in support of a conclusion about domestic constitutional law. Discussion of this rather limited use of international law—far short of the notion that “[i] nternational law is part of our law”—implicates a deeper set of questions about democracy, sovereignty, and sources of law: Is recourse to international sources a fundamental affront to notions of democratic self-rule, or is it the natural development of a maturing legal system—one moving toward new understandings of sovereignty and popular sovereignty appropriate to an increasingly interconnected web of transnational legal relations? I will argue here for the latter position, and from this perspective the occasional illustrative citation to international norms in the course of a conventional constitutional law opinion is an invitation to broader thought more than a fire bell in the night.

On May 28, 2003, President Bush issued Executive Order No. 13,304 under the International Emergency Economic Powers Act (IEEPA), thereby “blocking” the property of individuals who, he determined, threatened efforts to bring stability to the Balkans. The blocking order prohibited U.S. citizens from, among other things, “making or receiving… any contribution or provision of funds, goods, or services to or for the benefit of” any of die targeted individuals unless the U.S. citizen received a license from the U.S. government. Included in the list of targeted persons were more than eighty individuals indicted by the International Criminal Tribunal for the Former Yugoslavia (ICTY). EO 13,304's sweeping prohibition on U.S. citizens’ economic relations with die targeted persons consequently appeared to ban U.S. lawyers from representing virtually any defendants being prosecuted at the ICTY—a ban mat would have required the twenty or so U.S. lawyers widi such clients to break off their representation immediately, regardless of die stage that their cases had reached. Indeed, the U.S. Treasury Department office that administers IEEPA blocking orders informed three U.S. attorneys representing a client in a complex, lengthy appeal that, without a license, dieir continued representation of that client constituted a “prohibited exportation of legal services” and thus violated the order and its accompanying regulations.