This paper focuses on the relationship between agency and knowledge within the context of rising nationalism and populism. The case is the Czech debate over the reintroduction of civil defence education (CDE). It was abandoned in 1989 but recently, many new and contradictory calls for its return have appeared. We aim to gain an understanding of what the nationalising of education does with actorship in educational governance and how agency is achieved in pushing or criticising nationalist claims in education. The dataset consists of media entries, strategic documents, and interviews. We argue that the populist repertoire intervened significantly in "defining" what is the problem that some groups wanted to solve by a renewal of CDE. This situation stabilised the position of security-military expertise as reasonable knowledge, which concealed the educational nature of the problem and thus denied educational actors a role in agency. The role of the state structures responsible for education was problematised and set the difference of the Czech case in the European context regarding educational governance. We conclude that contemporary nationalists' claims concerning education may be seen as a sign of the changing role of expert knowledge that camouflaged defence education as an educational problem.