The aim of this paper is to examine the relationship between Czech presidents and prime ministers (and governments) in foreign policy-making during international conflicts. At the same time, this specific area of foreign policy is used to show the role and limits of presidential activism. The basic starting point is executive dualism, i.e. an analysis of the structure of the executive with an emphasis on the mutual conflicts between the two branches and possibly other constitutional institutions. The aim is to point out possible systemic risks arising from the fact that foreign policy in the Czech Republic is entrusted to the president and the government. The paper focuses on several selected military conflicts, e.g. the Kosovo war, the Russian annexation of Crimea and the war in eastern Ukraine, the Russian-Ukrainian war.