This chapter outlines the content of the written Constitution and describes the historical context, debates, and compromises from which the Constitution emerged. A central theme involves the emergence of “judicial supremacy” or the dominant role of the Supreme Court in constitutional interpretation. At the time of the Constitution’s ratification, many people believed that each of the branches of the national government would interpret the Constitution for itself. Moreover, the Supreme Court was not initially regarded as a particularly important institution. In order to explain the rise of judicial supremacy, the chapter begins to develop the idea, borrowed from political scientific literature, that the Court’s power exists within and is constrained by politically constructed boundaries that are constituted by the willingness of other institutions and ultimately the American people to accept the Court’s rulings as authoritative. In support of the argument that the Court’s power to interpret the Constitution authoritatively depends on the support of political officials and the American public, not the clear mandate or logical implications of the constitutional text, the chapter debunks the myth that the Supreme Court’s 1803 decision in Marbury v. Madison definitively settled the question of the Court’s interpretive authority.