A model of foreign policy substitutability: Selecting the right tools for the job(s)

The authors present a model of substitutability that seeks to generalize beyond the restricted conditions and special case of realism. The derivations from the model lead to several hypotheses. First, if a state's relative capabilities increase, resources given to all foreign policies should increase. Second, when the efficiency of one policy increases, resources given to other policies should decline. Third, when the relative salience for one good increases, resources devoted to policies that produce that good should increase, while resources devoted to policies that produce other goods should diminish. The authors use the model to guide an investigation of the effects of increased resources, new alliances, and more efficient existing alliances on the policies of conflict initiation and increases in military spending. The findings are inconsistent with realism's version of substitutability but can be explained by an n-good approach.