Legal regulation of Ukrainian citizenship in conditions of war and mass migration

It is determined that the mass external migration of Ukrainian citizens caused by the full-scale war with Russia since 2022 has led to profound legal challenges, particularly in the area of citizenship. The article examines the main problems related to multiple citizenship, the risks of statelessness, difficult access to personal documentation, and the realization of the rights of displaced persons. Particular attention is paid to the contradiction between the principle of single citizenship enshrined in the Constitution of Ukraine and the real conditions under which millions of citizens have actually acquired citizenship of other countries. The difficulties arising in the registration of births, the restoration of lost documents, the confirmation of citizenship, and the consequences of forced passportization in the occupied territories are analyzed. The influence of international law, in particular the 1951 and 1954 Conventions, on the formation of state policy regarding refugees and stateless persons is considered. The article also outlines the problems of exercising electoral, social, and labor rights of Ukrainians abroad. In the context of full-scale war, the Ukrainian legal system must adapt to new realities by revising legislation on citizenship, internally displaced persons (IDPs), civil status registration, and social protection. The article proposes possible areas for reform, including the introduction of flexible systems for recognizing multiple citizenship without automatic punishment, the creation of a single digital register of IDPs, the simplification of procedures for restoring lost documents, and international coordination in the field of legal protection of citizens. It notes that the war has created an urgent need to modernize legislation aimed at ensuring legal identity, simplifying identification procedures, creating digital registries, and strengthening international coordination. The importance of creating effective mechanisms for the protection of citizens, regardless of their location, especially in conditions of legal uncertainty, is emphasized. It has been determined that the preservation of citizenship and legal ties with the state are key conditions for the stability of Ukrainian statehood, the restoration of trust in state institutions, and effective post-war reintegration.