Two logical problems appear to have impeded the development of an integrative understanding of international and foreign policy phenomena. The first has to do with the potential for foreign policy substitutability: through time and across space, similar factors could plausibly be expected to trigger different foreign policy acts. The second concerns the potential existence of “sometimes true,” domain-specific laws. It is the logical opposite of the substitution problem, suggesting that different processes could plausibly be expected to lead to similar results. Neither problem appears to be well understood in the current literature; if anything, both are ignored. Nevertheless, they are potentially important. Together, they suggest that scholars who are interested in developing a cumulative base of integrative knowledge about foreign policy and international relations phenomena need to rethink both their focus on middle-range theory and their application of the standard approaches. We recommend reconsideration of some of the “grand” theoretical approaches found in the “traditional” literature. A new synthesis of tradition and science and of grand, middle, and narrow approaches appears to be needed. Finally, in contrast to the arguments of proponents of a systems-level approach, we argue that the most fruitful avenues for theorizing and research are at the microlevel in which the focus is on decision making, expected utility calculations, and foreign policy interaction processes.