But 9/11 also changed nothing, because what those who study political science and law suddenly discovered has always been there. Constitutional law and American foreign policy have been intimately related since Alexander Hamilton and James Madison (writing as Pacifi cus and Helvidius) battled over President George Washington’s decision to proclaim neutrality in the confl ict between England and France in 1793 (Hamilton and Madison 2007). The Supreme Court itself has played an important role in these debates, setting the parameters for the exercise of national power, as well as the allocation of that power among and between the branches of the national government. Indeed the Court’s role dates back at least to 1804 when Chief Justice John Marshall ruled for the Court that orders given by the president during America’s quasi-war with France (DeConde 1966; Alfange 1996) “cannot change the nature of the transaction, or legalize an act which without those instructions would have been a plain trespass” (Little v. Barreme 1804). Though Congress had written a statute that seemed unlikely to achieve the ends Congress itself likely intended, Marshall ruled that this was well within congressional power, and that the president had no constitutional authority to reinterpret the law.