This paper provides a theoretical explanation of what causes historical issues to impact bilateral relations between two states. The case which was chosen for analysis – popularly known as the Katyń issue – involves changes in Polish foreign policy towards the Russian Federation due to the remembrance of the Katyń Massacre. The main assumptions are based on the concept of securitization and its analytical framework, particularly the societal portion, which is proposed by the Copenhagen School of security study. The process of European integration can be seen as the main causal factor leading to a complex of vertical and horizontal competition between Poland, the EU, and Russia over the construction of their historical identities with a referent object of securitization in Poland. The main conclusion of this paper suggests that significant differences in the understanding of various nations’ roles in WW2 between the EU and Russia have led to the securitization of the Polish historical image of WW2. The Polish audience considered it important to accept the historical truth. The Katyń issue in Polish–Russian relations has become a case that reflects the process which leads to securitization of disputes between historical victims and victimizers on a state–to–state level.