Internationalism is the view that institution-building and peaceful cooperation will make peace and security prevail in a system of independent states. This book examines this controversial topic and discusses whether such a view is realistic or whether international relations are typically characterised by tension and war. Kjell Goldmann seeks to examine the plausibility of internationalism under present-day conditions. A theory of internationalism is outlined and is shown to have two dimensions: one coercive (to enforce the rules and decisions of international institutions) and one accommodative (to avoid confrontation by means of mutual understanding and compromise). Problematic features of the theory are then considered in detail: the assumption that all international cooperation tends to inhibit war, and the tension inherent in the joint pursuit of coercion and accommodation.