Realist environment, liberal process, and domestic-level variables

This article examines the deductive basis upon which domestic-level theorizing may be combined with liberal and realist systemic-level theory in order to account for international outcomes. It is particularly concerned with whether existing systemic theory can incorporate domestic-level variables in a causally consistent rather than ad hoc manner. In addressing such a concern, it confronts the widely held assumption in the IR theory literature that liberalism is more accommodating of domestic-level variables and their potential causal impact than is realism. When the deductive logic of systemic liberal and realist theory is examined, however, it becomes clear that domestic-level variables can be consistently causal in systemic realist theory, but are accorded little causal weight in systemic liberal theory. The article concludes that realism is actually more accommodating of domestic-level variables and theorizing than is liberalism. Given the common misconceptions within the field regarding the relationship between systemic theories and domestic-level theorizing, issues of theoretical causal compatibility must be considered if domestic-level variables are going to be incorporated in a rigorous rather than ad hoc manner.