The article discusses debatable theoretical and complex practical problems associated with the implementation of the “right of peoples to self-determination”: the absence of a generally accepted definition of a “national minority”; a way to identify the “will of the people” to self-determination; the relationship between the borders of the state and the borders of nations; national self-determination and democracy; the right to national self-determination and the right to popular sovereignty; the compatibility of individual rights, the rights of national minorities to self-determination and the principle of the inviolability of state borders. As a result, the author comes to the conclusion that there is no one “only true” form of solving these problems, ideally, the people make the choice (in practice, their political elite) based on a large number of (sometimes not completely rational and even random) factors. However, the most important issue is to solve the problem of effective representation of ethnic groups’ / national minorities’ interests, since ethnic groups and other minorities are alienated when their access to power is limited. Author considers that for to solve this problem in states, that respect human rights, ethnicity must have only cultural, not political importance, because the subject of political sovereignty in these states is not “ethnos” but “demos”, so that is, all citizens of the state who may belong to different ethnic and cultural communities. That’s why the organic combination of collective rights of ethnic communities and minorities in multi-ethnical and polycultural society with the rights of individuals guaranteed and protected by the state is the most suitable way to provide democratic policy. This policy doesn’t lead to the formation of new ethnic nations and the emergence of new ethnocratic states. In that situation, inter-ethnic relations must not be based on an ideal model but on existing ethnopolitical reality and using the existing potential of existing imperfect political institutions.