Determining when states can use force legitimately is the central normative problematic in world politics. Domestically, constraining the state’s use of force with social and legal norms that confine state-sanctioned violence to a limited and clearly defined set of purposes and circumstances is essential to the maintenance of civil society and the protection of basic human rights. Internationally, circumscribing the conditions under which states may use force legitimately is critical to the maintenance of peace and stability in international society. And the degree to which legitimate force may be used internationally to constrain illegitimate force domestically lies at the heart of the problematic relationship between order and justice in world politics.