Between the Threat for Sovereignty and Regional Leadership: Ukraine and Russian Integration Projects in the Post-Soviet Space

The purpose of the study is to analyze the role and participation of Ukraine in integration projects in the post-Soviet space - the Commonwealth of Independent States (CIS), the Eurasian Economic Community (EurAsEC), the Common Economic Space (CES), the Collective Security Treaty Organization (CSTO), GUUAM / GUAM. Scientific novelty. Despite the fact that Ukrainian and foreign historiography of the subject under study has found its researchers since the first years after the collapse of the USSR, its comprehensive study is still lacking, especially considering the changes that occurred in the post-Soviet space after 2014 - with the beginning of the Russian-Ukrainian war, which reached a full-scale level on February 24, 2022. Conclusions. During the 1990s and 2010s, the Russian side failed to completely "reintegrate" Ukraine into the sphere of its geopolitical interests after the collapse of the USSR by creating economic (with the prospect of development to the level of political) alliances. While the Kremlin saw the CIS, the EurAsEC, the CES (and even more so the Eurasian Union) as tools to restore its geopolitical influence after the collapse of the Soviet Union, including through the creation of supranational bodies in these associations, the Ukrainian side was interested exclusively in the economic aspects of the activities of these organizations - primarily in the creation of a Free Trade Area. This fundamental difference in approaches explains why the Ukrainian state, having actively participated either in the creation or participation in the organization as an observer, has never become a full member of such Russian-inspired associations. The idea of integrating Ukraine into the structure of the CSTO was also unrealized. During the years of V.Yanukovych's presidency, it was embodied only in the creation of the Ukrainian representative office of the Institute of this Organization. Instead, within the framework of GUUAM / GUAM activities in Ukraine, there is a chance to become a real regional geopolitical leader and an important coordinator within the organization, especially against the background of the outlined European and Euro-Atlantic course of official Kyiv, which is established on the battlefield with the Russian aggressor.