Author's Note: War has been the primary focus of the scholarly study of international relations (IR) from its very beginning. E.H. Carr and his colleagues at Aberystwyth created the first IR department in 1919 in the wake of the Great War at least partially in the hope of preventing the next one. Their lack of success did not keep war and from becoming the primary issues of study for most students of international politics ever since. Conflict has been the direct or indirect topic of much of the work that IR scholars have produced during the last century and, indeed, has been one of the main reasons why many of them entered the field in the first place. If the fundamental nature of warfare were to change, therefore, one would expect repercussions in the field of IR. The obsolescence-of-major-war argument, which found renewed energy with the publication of John Mueller's Retreat from Doomsday, seems to describe one such fundamental change. The suggestion that the great powers may have put war behind them has been debated at some length over the past 17 years, with its many skeptics pointing out that such optimistic ideas are not new. Prior articulations of perpetual peace have always been eventually proven wrong by war's depressing proclivity for resurrection. Supporters have not moved far beyond basic explanations of the argument, at least to this point, in large part because its nature seems to preclude definitive proof or falsification. It is, after all, a theory of the future as much as of the present. The development of the argument has stalled in the time since Mueller's book was published, with a number of key questions remaining unanswered. Would state behavior remain unchanged absent the realistic possibility of major war? How would the study of international politics need to be adjusted to describe accurately an age of great power peace? In other words, what if Mueller is right? In some senses, therefore, this forum is an exercise in conjecture and speculation. It asks the reader to accept the argument--ifjust for a moment--that the great powers have put warfare behind them, at least in their interactions with one another. For some, this will require a nearimpossible stretch of the imagination; for others, it will be a logical and overdue recognition of modern reality. If it is true that many nations no longer consider fighting such wars, then many of our central beliefs about state behavior will have to be rethought and adjusted to better describe twenty-first century realities. This forum contains three parts. (1) The first explores the current state of the argument and its critics and speculates on its importance to a field traditionally focused upon the great powers, discussing the reasons to believe that the obsolescence of major war may eventually lead to the obsolescence of all war. (2) The second contains multiple parts, each of which proposes a central theoretical implication of the obsolescence-of-major-war argument and considers the ways in which some of the major theories and debates in the field would be affected if the great powers prove stubbornly insistent on conducting peaceful relations. A new conception of power itself may be in order; for instance, one that makes a distinction between the potential and kinetic power of a state. This argument also has implications for the relative vs. absolute