Revisiting the Arms Race Richardson's Model: Beyond the two actors' approach

Beyond the two actors' approach

Abstract

Richardson's model is classical in the eld of International Relations, which describes arms race between two actors, by means of system of ordinary dierential equations with constant coecients of the respective military budgets. In this paper, we extend Richardson's model to comprise an arbitrary number of actors to investigate whether there are scale properties that arise when multiple actors are considered, rstly by treating the special case when the actors are undierentiated, then the case of dierentiated actors. We report that, as the number of actors increases, there is no guarantee that individual budgets will not tend to increase limitlessly, which is a theoretical result not present in the original model and presents new possibilities of thinking about the boundaries of international system stability.