In Part III, this book will internationalize U.S. law. As demonstrated in Part I, the U.S. federal court system is an international tribunal system with interstate and national dimensions. In Part II, this book provided a transitional discussion of international law in general in order to provide a template against which to analyze U.S. law. In Part III, this book will demonstrate that U.S. federal law is international law with interstate and national dimensions. Like other international tribunals, U.S. federal tribunals exercise jurisdiction over positive international law claims and sometimes even natural law of nations claims. In exercising such jurisdictions, both international and U.S. federal tribunals have developed a number of interpretive principles. In the following chapters, we will examine these how these jurisdictions and principles overlap and differ.

The U.S. federal courts exercise both federal law claims and party-based jurisdictions. The judicial power of the federal courts is set out in Article III of the Constitution, which states in relevant part: