In the history of Ukrainian people, with their centuries-long tradition of national State-building, the Perestroika period (1985–1991) was special in the sense that in those times there were processes which resulted in the destruction of the excessively centralized State which, in fact, the then Union of Soviet Socialist Republics (USSR) was, and also given that favorable conditions emerged for the proclamation of Ukraine’s independence.

The article aims at highlighting the process of gradual expansion of powers of the supreme public and administrative authorities of the Ukrainian Soviet Socialist Republic (UkSSR) with regard to lawmaking, in particular, those which ensured a high level of its sovereignty and, in the long run, drove the Republic to declare its independence.

Having analyzed the provisions of the USSR Constitution, 1977 and the UkSSR Constitution, 1978, the author established that at the beginning of Perestroika, the Union public and administrative authorities were given extremely broad powers to create an extensive system of Union legislation which regulated almost all areas of State-, economic, social and cultural building in the country. The Union Republics, including the Ukrainian SSR, had little left for their own rule-making activities at the national level. The article outlines the provisions of the Union and Republican Constitutions which ensured the supremacy of the Union regulatory framework and prevented any deviation of UkSSR legislation from requirements of USSR legislation. The author puts a particular emphasis on Article 71 of the USSR Constitution which declared categorically that laws of the USSR were mandatory in the Ukrainian SSR territory. It is proved that the constitutional supremacy of the Union legislation naturally entailed the situation when a huge quantity of Union legal acts of diverse legal nature were in effect in the Ukrainian SSR territory, in particular, primary legislation of the USSR and the Union Republics in all of the main branches of law. Such expansion of the Union legislation within Ukraine’s territory did not stop almost until the collapse of the USSR.

The article proves that as Perestroika progressed entailing the deployment of democratic processes, there obviously arose the need to abandon the Stalinist model of the Union State and transfer it to the status of a truly Federal State with further expansion of the rights of the Union republics, including those which they had with regard to lawmaking. The article analyzes the content of the Law of the USSR “On Delineation of Powers Between the USSR and Constituent Entities of the Federation”. The author demonstrates that by this legal act, the Moscow Union State Party leadership pretended to pursue the policy of improving the relations between the USSR, represented by its supreme public and administrative authorities, and the Union Republics, but in fact implemented the policy of preserving the broad powers of those bodies, including in the law-making area.

It is established in the study that under the conditions of Perestroika, the then Kremlin leadership, being forced to implement the maneuvering tactics in resolving the issues of interethnic relations, decided to demonstrate its ability to ensure that the Union Republics could exercise their constitutional right to secede from the USSR. The withdrawal of the Ukrainian SSR from the USSR would mean that the Republic completely renounced the Union legislation. The article analyzes the Law of the USSR “On the Procedure for Resolving Issues Related to the Secession of the Union Republic from the USSR” and substantiates the conclusion that it was almost impossible for Ukraine to exercise its right to secede from the USSR in accordance with this Law.

It is noted that after the adoption of the Declaration of State Sovereignty of Ukraine on July 16, 1990, Ukraine began actively distancing itself from the Union center in all areas of State-building, and this was reflected in the changes of and additions to the Constitution of the USSR and logically entailed the adoption by the UkSSR’s Verkhovna Rada of the historical document on August 24, 1991 – the Act of Proclamation of Independence of Ukraine which, along with independence of the country, proclaimed the establishment of the sovereign Ukrainian State -Ukraine.

Within the study, the author analyzed the Law of Ukraine “On Legal Succession of Ukraine” and the Resolution of the Verkhovna Rada of Ukraine “On the Procedure of Interim Validity of Separate Acts of USSR Legislation in the Territory of Ukraine”; they, so to speak, opened the way for the independent Ukraine to dismantle the Union legislation which for many years dominated in the Republic that was held in the grip of the State known as “the USSR” with its dominating administrative command system of administration.