This paper studies the different roles, impact, and operation of bilateral treaties and multilateral treaties as structures within the architecture of international law. I observe that the preference for bilateralism or multilateralism in international lawmaking is often determined not by an informed choice but by an instinctive association of political schools or bureaucratic affiliations with different forms of international regulation. This association, however, is not always founded on a just appreciation of the workings of either form in various contexts or of the way in which the two interact with each other. I set out to offer a framework for such an appreciation and assess the workings of multilateral treaties and bilateral treaties along three dimensions: the contribution of the respective instruments to the advancement of an international rule of law; the operation of the regime in terms of its effectiveness, efficiency, and compliance; and the democratic legitimacy of the making of each regime. I demonstrate that ideologies and values that seem to be almost blindly associated with one type of regulation may be actually better served, in some cases, by using the other type. Ultimately, this paper attempts to chart a course for more theoretical and empirical forays into the questions of why states join particular types of treaties and how these different types of treaties, or a combination of them, promote or obstruct the attainment of various goals within the architecture of international law.