Relevance. The crisis of the modern European sovereign nation-state is defined as existential (not "technical"); therefore, we should talk about a socio-philosophical study of the "crisis of the foundations". The purpose of the article is to present the non-reality of the foundations of the nation-state in modern times, totally determined by the dominant liberal economic paradigm of the political (J. Agamben), and modern ways of removing the consequences of the political crisis in the liberal tradition. The objective is based on the interpretation of these statements - to determine the conditions and boundaries of the possibility of "response" from the perspective of "liberal metaphysics". Methodology. According to K. Schmitt, liberalism is "consistent metaphysics", the essence of which is defined as "endless free / public discussion"; a consistent liberal "response" to the challenge, therefore, can only be given on the basis of the named "essence" ‒ the main methodological position that determines the structure and content of this article. Results. It was revealed, that a nation as a form of political unity of a sovereign people, in the perspective of liberal metaphysics, cannot be relied on as a "substance of the state". That the people-sovereign is "split in itself" and the available ways of actualizing its real unity are no longer "valid". That the mechanisms of political representation that democratically legitimize the power institutions of a sovereign nation-state in its new European, that is, liberal, form, need radical reform. "Free discussion", stated in the article, is limited in the possibility of "answering" the "existential crisis"; this presupposes the need to reduce the "political" (Schmitt's "concept of the political" as an "existential solution" of the sovereign in the horizon of the existential opposition "friend – enemy") and "reduction" by means of such a reduction of the "essentially political" to technical issues of "governance" (M. Weber). Three main methods of "liberal reduction of the political" are distinguished: "logical-epistemological" by Y. Elster, "ethical" by J. Rawls, "aesthetic" by R. Ankersmit, and their characteristic "features" are determined. Conclusion. It is concluded that a consistent liberal political philosophy, losing in its understanding of politics as government, the distinction between auctoritas and potestas, is unable to thematize the "existential", that is, political, crisis of the foundations of a sovereign nation-state.
