Tax Constitutionalism in the Context of the Transformation of the Paradigm of Constitutionalism: Contradictions, Trends, and Prospects for Institutionalization at National and Supranational Levels

One of the least studied yet simultaneously key aspects of the constitutionalism transformation is the phenomenon of tax constitutionalism. In the context of growing fiscal pressure, asymmetry of tax regimes, and the increasing supranational influence on tax policy, the question of the limits of permissible state intervention in citizens' economic freedom from the perspective of the constitution becomes more acute. Historically formed as a form of expression of the social contract and legitimization of public authority through taxation, tax constitutionalism acquires new significance in the era of the crisis of representative democracy and the rise of executive discretion. The subject of this research is the constitutional and legal foundations, law enforcement practices, and prospects for the institutionalization of tax constitutionalism in the context of the transformation of foundational principles of modern constitutional order. The methodological basis of the study is a systemic approach, which implies considering tax constitutionalism as a complex legal institution located at the intersection of public and constitutional law. Comparative legal, axiological, and institutional methods of analysis are applied to identify the evolution of norms and mechanisms of tax legitimization in various jurisdictions. The scientific novelty of the research consists in substantiating tax constitutionalism as an independent concept reflecting the adaptation of constitutional order principles to new challenges of public governance. The article makes the first attempt to systematize the characteristics and models of tax constitutionalism, taking into account the differences between national and supranational fiscal systems. The author shows that modern tax constitutionalism implies not only compliance with formal procedures but also the realization of values of justice, proportionality, and fiscal sustainability. The necessity of constitutional oversight over fiscal innovations, including digital taxes, climate fees, and platform taxation regimes, is substantiated. It concludes that the further development of tax constitutionalism is only possible under conditions of institutional consolidation of mechanisms for public participation and legal transparency. Overcoming existing contradictions requires the development of balanced models of fiscal sovereignty that are compatible with the principles of constitutional identity. The research aims to develop the theory of adaptive constitutionalism as a foundation for a sustainable tax order in the 21st century.