become a union republic and was made into an autonomous republic of the RSFSR, although the Crimean Tatars had a relative majority until the 1930s or 1940s according to censuses. When the Tuvan People's Republic joined the Soviet Union in 1944, it did not become a union republic, and was instead established as an autonomous republic of the RSFSR. The leader of the People's Republic of Bulgaria, Todor Zhivkov, suggested in the early 1960s that the country should become a union republic, but the offer was rejected. During the Soviet–Afghan War, the Soviet Union proposed to annex Northern Afghanistan as its 16th union republic in what was to become the Afghan Soviet Socialist Republic. Unrealized Soviet states Bessarabian Soviet Socialist Republic (1919) Polish Soviet Socialist Republic (1920) East Polish Soviet Socialist Republic (1990) Autonomous Republics of the Soviet Union Several of the Union Republics themselves, most notably Russia, were further subdivided into Autonomous Soviet Socialist Republics (ASSRs). Though administratively part of their respective Union Republics, ASSRs were also established based on ethnic/cultural lines. According to the constitution of the USSR, autonomous republics, autonomous oblasts and autonomous okrugs had the right, by means of a referendum, to independently resolve the issue of staying in the USSR or in the seceding union republic, as well as to raise the issue of their state-legal status. Former Autonomous Soviet Socialist Republics of the Soviet Union Dissolution of the Soviet Union Starting in the late 1980s, under the rule of Mikhail Gorbachev, the Soviet government undertook a program of political reforms (glasnost and perestroika) intended to liberalise and revitalise the Union. These measures, however, had a number of unintended political and social effects. Political liberalisation allowed the governments of the union republics to openly invoke the principles of democracy and nationalism to gain legitimacy. In addition, the loosening of political restrictions led to fractures within the Communist Party which resulted in a reduced ability to govern the Union effectively. The rise of nationalist and right-wing movements, notably led by Boris Yeltsin in Russia, in the previously homogeneous political system undermined the Union's foundations. With the central role of the Communist Party removed from the constitution, the Party lost its control over the State machinery and was banned from operating after an attempted coup d'état. Throughout this period of turmoil, the Soviet government attempted to find a new structure that would reflect the increased authority of