Abstract: This paper addresses the interplay between unilateralism and multilateralism. I describe their stylised facts and present a simple, multi‐country model with high initial tariffs and features that have always been of paramount concern to policy makers, and allow governments to negotiate multilateral agreements. I then find a role for a system with features remarkably similar to contemporary unilateralism. The relationships between multilateralism and unilateralism are subtle: Unilateralism has the properties it has because the world is multilateral (the insurancetriangle); useful unilateralism requires a multilateralcomponent resulting from a compatibility problem between those who negotiate multilaterally and those who establish unilateralism.