The United States has in recent years come under considerable criticism for its apparently cynical attitude towards international law. While the US administration refers often to the importance of the international rule of law it appears unwilling to itself be bound by that law. While the US took the lead in the post World War II years in establishing international law and institutions it has in recent years appeared unwilling to give those same institutions its full support. This article begins by examining a range of explanations for the seemingly undesirable US attitude towards international law. Dismissing each as inadequate on its own, the article demonstrates how what often appear to be contradictory aspects of the United States' relationship with international law can in fact be reconciled through the application to United States' behaviour of the basic tenets of classic modern realism as it pertains to the conduct of foreign policy. This is surprising since international law and realpolitik are more often contrasted. The United States' ‘attitude’ towards international law is better explained not as a post-Cold War anomaly but as having been an integral aspect of the rise of the United States to sole superpower status.