The author discusses dubious consequences of western approaches being affirmed in Russian science, to the study of ethno-national processes and in this connection places the question of expected “length of life” of post-Soviet ethno-nationalism in the focus of analysis. Those who uncritically accepted the “imported” models produced by specializing nation-students, he notes, come out with conclusions that it has established itself to stay for many decades henceforth, and the conclusions in question, in his estimation, are underlain by incomprehension of the differences between societies that are on the way from traditionalism to modernity, and the already modernized sociums to which, undoubtedly, belong the post-Soviet ones, notwithstanding certain spoilage inherent in their modernization. Due to the essentially different socio-cultural dynamics of the now forming world “post-national expanse”, and to the completely different “historical rates of movement”, the author argues, the “length of life” of post-Soviet ethno-nationalism will be much lesser than that of its classical “ancestors”, and its “force field” appreciably weaker.