Supporting the proposition that deprivation of citizenship “has grave practical consequences,” Justice Arthur Goldberg wrote: “The drastic consequences of statelessness have led to reaffirmation in the United Nations Universal Declaration of Human Rights, Article 15, of the right of every individual to retain a nationality.” Justices Potter Stewart and Byron White dissented, but did not criticize the reference to international law. As the chapters in this book show, the U.S. Supreme Court has routinely referred to international law in cases interpreting the Constitution throughout the nation's history, without the references occasioning controversy for departing from accepted standards of constitutional interpretation.

In light of this history, the fact that references to non-U.S. law in Lawrence v. Texas and Roper v. Simmons provoked a strong critical response is striking. The reaction, not the references, illustrates a change in the role non-U.S. law plays in constitutional interpretation – or, more precisely, in discourse about constitutional interpretation. A practice that occasioned no significant controversy for two centuries did so early in the twenty-first. One possible explanation, of course, is that Lawrence and Roper referred to non-U.S. legal materials in a different manner from the earlier cases. In the discourse that has developed, Lawrence and Roper “used” non-U.S. materials differently and inappropriately. Consider here the way in which Supreme Court nominee Sonia Sotomayor addressed a question about the “use” of non-U.S. materials in constitutional interpretation.