UNILATERALISM IN A MULTILATERAL WORLD
用一个多国模型分析单边主义与多边主义的互动，发现单边主义之所以有效，恰恰因为世界是多边的，且单边主义需要多边成分来克服谈判中的兼容性问题。
This paper addresses the interplay between unilateralism and multilateralism. I first describe theirrespective stylized facts. I next present a simple, multi-country model with high initial tariffbarriers and with the features that have always been of paramount concern to policymakers, allowgovernments to negotiate multilateral agreements, and analyze the resulting equilibrium. I thenconsider the possibility of unilateralism and find a role for a system with features remarkablysimilar to contemporary unilateralism. The relationships between multilateralism and unilateralismare subtle: Unilateralism has the properties it has because the world is multilateral (the insurancetriangle); to be useful unilateralism requires a multilateral component of some type; this typeresults from a basic compatibility problem between those who negotiate multilaterally and thosewho establish unilateralism.