The question of how foreign policy is determined is a crucial one in world affairs. In these comments, I can only provide a few hints as to how I think the subject can be productively explored, keeping to the United States for several reasons. First, the U.S. is unmatched in its global significance and impact. Second, it is an unusually open society, possibly uniquely so, which means we know more about it. Finally, it is plainly the most important case for Americans, who are able to influence policy choices in the U.S.—and indeed for others, insofar as their actions can influence such choices. The general principles, however, extend to the other major powers, and well beyond.