The article is devoted to the historical and legal aspects of territorial development of the Russian state, in particular, the territorial development of the USSR during the period from 1936 until 1947. The article examines the pre-war period of escalation of confrontation in the world, the immediate beginning of the Second World War (and the conflicts accompanying it), the entry of the USSR into the WW II, the end and the first post-war years, when territorial changes received legal formalization. The article analyzes the constitutional law regulation of territorial issues in the USSR in the conditions of the World War II, the efforts of the Soviet state for the integration and protection of territories, as well as their socio-economic and industrial development. The World War engulfed many countries, but at the same time, the national science of each country explores problems, including world phenomena, primarily from the standpoint of the history of its country. In this study, an attempt is made to evaluate responses of the Soviet state and society to the challenges of the middle of the last century in the context of the state law and the possibility of using historical and legal experience in modern conditions. Both in the middle of the last century and today, the confrontation between countries, their unions, and social groups reached a maximum. The problem of accelerating technological development, import substitution, and the growth of production capacity remain equally serious challenges for the Russian state. In the last century, our country coped with all the challenges, but they have arisen again. Nevertheless, the author believes that the global instability prevailing in the modern world stimulates research aimed at comprehend the historical events of the two World Wars in order to unite the efforts of expert communities from different countries to reduce the risks of the Third World War escalation.