Arms Races: External Security or Domestic Pressure?

Arms races have been the subject of many and various explanations, but of few formal theories which manage to combine the virtues of plausibility and parsimony. Perhaps the best known is Richardson's, to which interesting modifications have been proposed by Smoker, Saaty and most recently Hamblin et al.2 Common to all these models is the assumption that arms races can be explained by an action-reaction process between the two nations involved.