1. Introduction What is the role of a foreign policy ideal--democracy promotion--in shaping public opinion on foreign policy? (1) The experience of the 9/11 attacks on American soil, the ensuing wars against Iraq and Afghanistan, and the Bush administration's adoption of a new foreign policy doctrine brought the ideal of democracy promotion to the forefront of American foreign policy. While studies of public opinion on foreign policy have focused mainly on examining the existence of organized belief systems and the reasonableness of public opinion in foreign affairs, we know little about the role of democracy promotion in forming public opinion. The experience of the Bush administration's emphasis on democracy promotion in U.S. foreign policy and the debate about the role of idealism and realism in accounting for citizens' opinion on foreign policy demands a closer examination of the role of belief in this ideal in shaping public opinion in foreign policy. In addition, the way in which citizens' belief in democracy promotion defines their opinions on foreign policy also needs to be elaborated. Specifically, it is necessary to explore the working mechanisms of this ideal goal in relation to political context. In studying public opinion on foreign policy, a major concern has been whether the mass public can make reasonable decisions. The majority of studies have attempted to counter negative views on the capacity of the mass public to do so. Lippmann (1955), Almond (1960[1950]), and Converse (1964) criticized public opinion on foreign policy as unstable, unorganized, and unreliable due to the lack of interests, information, and ideological constraints. However, along with the emerging studies that emphasized positive views of mass public opinion regarding domestic policy (e.g. Kinder 1983, Feldman 1988), studies on public opinion on foreign policy shifted toward optimistic views by showing the existence of organized belief systems (e.g. Wittkopf 1986, Chittick, Billingsley, and Travis 1995, Holsti 1992), the role of social and psychological constraints in maintaining the belief systems (e.g. Hurwitz and Peffley 1987), and citizens' strategic and instrumental considerations in foreign policy choices (e.g. Jentleson 1992, Jentleson and Britton 1998, Herrmann, Tetlock, and Visser 1999). While these studies provide us with persuasive theories and evidence regarding the existence of structure and organization of the public's foreign policy attitudes and capacity to come up with reasonable decisions, they have a limitation in understanding the role of democracy promotion, since most of the studies that focused on the structure did not pay attention to the ideal itself, let alone to its role in shaping public opinion on foreign policy. This lack of interest in democracy promotion is ironic in that the debate about the relevance and effectiveness of idealism in American foreign policy has been around for a long time among scholars of international politics (e.g. Morgenthau 1952, Kennan 1984, Osgood 1953, Cox, Ikenberry, and Inoguchi 2000). Furthermore, democracy promotion is the core concern of liberal idealists (e.g. Cox, Ikenberry and Inoguchi 2000, Diamond 1992) and neo-conservatists (e.g. Kristol and Kagan 1996) alike. However, we know little about the characteristics and working mechanisms of this ideal in forming public opinion on foreign policy. What will be the effect of democracy promotion on foreign policy opinion? Under what conditions will the effect of the belief in this ideal be strengthened, weakened or remain stable in accounting for citizens' foreign policy choices? This study finds that individuals' belief in democracy promotion as a foreign policy goal plays a significant role in accounting for their support for U.S. troop deployments in defending allies from potential enemies and hostile countries. Also it shows that the effect of democracy promotion depends on political context. 2. …