There are compelling reasons for concern about the quality of law. Law is essential to structuring the social relations of the state. Thomas Jefferson famously wrote that life, liberty and the pursuit of happiness are God-given unalienable rights, and that the purpose of governments is to secure these rights on behalf of the governed. Whether the law of a state will be successful in this task depends upon the quality of that law. And, due to the vast changes in the international legal system so presciently anticipated by Wolfgang Friedmann in the 1960s, concern about the quality of law must, increasingly, focus not only upon national legislation, but also upon the formulation of rules and standards of international law as well. The thesis of this paper is twofold. First, it is that the various criteria that apply to assessing and improving the quality of national law, apply mutatis mutandis when addressing the quality of a multilateral treaty. In addition, I argue that the specific nature of the international legal system suggests that some additional, and special, “vertical criteria” should also apply. These revolve around three general pillars of legitimacy under contemporary international law. The first requires respect for the sovereignty-based notion of positivism as the basis of state obligations. The second requires respect for fundamental principle, which must be a characteristic of any true system of law purporting to promote justice, and the third in turn requires some reasonable accommodation of the practical policy-based necessities of cooperation in an interdependent world. The latter part of this paper will present a brief case study on the drafting of the Anti-Counterfeiting Trade Agreement (ACTA) in a first effort to apply this analytical framework.