A variety of studies suggest that a high need for closure—that is, a desire for knowledge that is clear, stable, and unambiguous as opposed to confusing or uncertain—may be associated with greater hostility toward relevant outgroups. Using international attitudes as the context, the authors examine the hypothesis that the relationship between the need for closure and support for military action against Iraq may be moderated by identification with the national ingroup. Specifically, it is expected that this relationship will be moderated by nationalism (i.e., an aggressive form of identification based on a desire for national dominance) but not patriotism (i.e., a more neutral love of one’s country). The data provided a clear pattern of support for this hypothesis and additional analyses indicated that a high need for closure reduced variability about the use of force among the highly nationalistic but not the highly patriotic.