FORM AND SUBSTANCE IN INTERNATIONAL AGREEMENTS

International agreements exhibit a wide range of variation. Many are negotiated as legally binding agreements, while others are expressly nonbinding. Some contain substantive obligations requiring deep, demanding policy changes; others demand little or simply ratify the status quo ante. Some specify institutions to monitor and sanction noncompliance; others create no review structure at all. Thus, there is considerable variation both in the form of international agreements-in their legal bindingness, as well as in the range of structural provisions for monitoring and addressing noncompliance-and in the substantive obligations they impose. This variation in form and substance raises several fundamental questions about the role of international agreements in world politics. ' Why do states differentiate commitments into those which are legally binding and those which are not? What relationship exists between legality and the substantive provisions of an accord, and between legality and structural provisions for monitoring behavior? What is the relationship between substantive obligations and monitoring provisions? Finally, what difference, if any, do these choices make as to the effectiveness of an agreement?

This article presents a conceptual framework for analyzing the architecture of international agreements. Using the concepts of form and substance, it examines three features of agreements, two related to form and one to substance. Legality refers to the choice between legally binding and nonlegally binding accords2 (for simplicity, I term this a choice between contratts and pledges). Substance refers to the deviation from the status quo that an agreement demands. Structure refers to provisions for monitoring and penalizing violators. Each of these terms represents a distinct design element. Yet there are systematic trade-offs among them. Only by understanding these trade-offs can we understand the design and operation of agreements.3 The framework advanced in diis article makes these trade-offs clear, while also reorienting current research in international law. For example, one area that recent scholarship has focused on is compliance with pledges.4 But without attention to the relationships between legality, substance, and structure, much of this work is inconclusive.5 In other areas where progress has been made, as in the choice of legal form, the prevailing explanations are incomplete and can be improved by accounting systematically for the connections between design features.

Using this framework, I make several claims about the architecture of agreements....