Historically, religious institutions have often played some role in determining the criteria for international justice during the war and in the post-war periods. The article aims to reflect theoretically on this phenomenon, drawing on the political theology of C. Schmitt (1888-1985) and the historical sociology of E. Rosenstock-Huessy (1888-1973). Both were prominent lawyers in Weimar Germany, but their paths diverged dramatically in 1933. They shared a view of the modern state as a restrainer of war. They also focused on the church and its role in stabilizing the new international order of the Westphalian era. The Westphalian approach to international justice rested on the idea of religious pluralism in terms of a plurality of sovereign states. It was important for Schmitt that the Roman Catholic Church (to which he belonged) recognized sovereign states and their right to declare war and make peace, even if it retained autonomy of doctrinal judgment and independent government. Unlike Schmitt, Rosenstock-Huessy believed that the main role in resolving religious conflicts was played not so much by the arrangements of sovereign states, but by the new organization of society that emerged as a result of the Reformation. This organization consisted of new social forms: the monarch-legislator, the civil servant, the civil authority, and the civil population. Rosenstock saw the separation of the military from the civil service as a kind of continental system of checks and balances that promoted international justice by limiting violence. After a historical and theoretical overview, the paper will analyze why the cultural role of ecclesiastical institutions is still important. Finally, it will be shown that the perspectives of political theology and historical sociology described above form a multi-confessional dialogue. The dialogical reflection on church and politics can be a contribution to the debate on international justice.