Do ideational factors shape the strategic choices of American leaders in the realm of national security policy? If they do, what perceptions and value dispositions guide choices toward critical countries like Russia, China, Japan, and Iran? Macrotheories of international relations make assumptions about the microprocesses at the decision-making level that are rarely examined empirically. For instance, do leaders decide based on their perceptions of an adversary's intentions as neo-realists claim or do they give greater weight to their perceptions of similar and different political cultures as advocates of the democratic peace assume? If ideational factors matter at all, are they independent forces or simply determined by demographics and/or parochial interests? This project reports the results of a survey of 514 U.S. leaders designed to answer these questions. We find that military assertiveness remains related to decisions to use force as it was during the Cold War but that a new disposition—attitudes toward free trade—has emerged as an even more robust predictor of these decisions as well as decisions to engage and contain. We find support for the microfoundations of neo-realist and image theory as well as for the idea that perceived culture matters. Our study also provides individual-level evidence for a micromechanism connecting trade to pacific choices.