Our adversarial system of international relations poses substantial risks of violent catastrophe and impedes morally urgent initiatives and reform collaborations. The domestic politics of more evolved societies provide guidance toward a better world governed by just rules, which ensure that basic human needs are met, inequalities constrained, and weapons and wealth marginalized as tools for influencing political and judicial outcomes. Impartial administration, adjudication, and enforcement of just rules require a strong normative expectation on officials and citizens to fully subordinate their personal and national loyalties to their shared commitment to the just and fair functioning of the global order. As we have fought nepotism within states, we must fight nepotism on behalf of states to overcome humanity’s great common challenges. To moralize international relations, states can plausibly begin with reforming the world economy toward ending severe poverty, thereby building the trust and respect needed for more difficult reforms.