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Nationality question and the Eastern Bloc

On taking power, Gorbachev found some unrest among different national groups within the Soviet Union. In December 1986, riots broke out in several Kazakh cities after a Russian was appointed head of the region. In 1987, Crimean Tatars protested in Moscow to demand resettlement in Crimea, the area from which they had been deported on Stalin's orders in 1944. Gorbachev ordered a commission, headed by Gromyko, to examine their situation. Gromyko's report opposed calls for assisting Tatar resettlement in Crimea. By 1988, the Soviet "nationality question" was increasingly pressing. In February, the administration of the Nagorno-Karabakh Autonomous Oblast officially requested that it be transferred from the Azerbaijan Soviet Socialist Republic to the Armenian Soviet Socialist Republic; the majority of the region's population were ethnically Armenian and wanted unification with other majority Armenian areas. As rival Armenian and Azerbaijani demonstrations took place in Nagorno-Karabakh, Gorbachev called an emergency meeting of the Politburo. Gorbachev promised greater autonomy for Nagorno-Karabakh but refused the transfer, fearing that it would set off similar ethnic tensions and demands throughout the Soviet Union. In the end however, greater autonomy was never given, and instead Gorbachev ordered the further violent ethnic cleansing of Armenians in parts of Nagorno-Karabakh and the adjacent Armenian-populated Shahumyan region, in what was named Operation Ring.

That month, in the Azerbaijani city of Sumgait, Azerbaijani gangs began killing members of the Armenian minority. Local troops tried to quell the unrest but were attacked by mobs. The Politburo ordered additional troops into the city, but in contrast to those like Ligachev who wanted a massive display of force, Gorbachev urged restraint. He believed that the situation could be resolved through a political solution, urging talks between the Armenian and Azerbaijani Communist Parties. Further anti-Armenian violence broke out in Baku in January 1990, followed by the Soviet Army killing about 150 Azeris. Problems also emerged in the Georgian Soviet Socialist Republic; in April 1989, Soviet troops crushed Georgian pro-independence demonstrations in Tbilisi, resulting in various deaths. Independence sentiment was also rising in the Baltic states; the Supreme Soviets of the Estonian, Lithuanian, and Latvian Soviet Socialist Republics declared their economic "autonomy" from the Soviet central government and introduced measures to restrict Russian immigration. In August 1989, protesters formed the Baltic Way, a human chain across the three countries to symbolize their wish to restore independence. That month, the Lithuanian Supreme Soviet ruled the 1940 Soviet annexation of their country to be illegal; in January 1990, Gorbachev visited the republic to encourage it to remain part of the Soviet Union.

Gorbachev rejected the Brezhnev Doctrine, the idea that the Soviet Union had the right to intervene militarily in other Marxist–Leninist countries if their governments were threatened. In December 1987 he announced the withdrawal of 500,000 Soviet troops from Central and Eastern Europe. While pursuing domestic reforms, he did not publicly support reformers elsewhere in the Eastern Bloc. Hoping instead to lead by example, he later related that he did not want to interfere in their internal affairs, but he may have feared that pushing reform in Central and Eastern Europe would have angered his own hardliners too much. Some Eastern Bloc leaders, like Hungary's János Kádár and Poland's Wojciech Jaruzelski, were sympathetic to reform; others, like Romania's Nicolae Ceaușescu, were hostile to it. In May 1987 Gorbachev visited Romania, where he was appalled by the state of the country, later telling the Politburo that there "human dignity has absolutely no value". He and Ceaușescu disliked each other, and argued over Gorbachev's reforms.

In August 1989, the Pan-European Picnic, which Otto von Habsburg planned as a test of Gorbachev, resulted in a large mass exodus of East German refugees. According to the " Sinatra Doctrine ", the Soviet Union did not interfere and the media-informed Eastern European population realized that on the one hand their rulers were increasingly losing power and on the other hand the Iron Curtain was falling apart as a bracket for the Eastern Bloc.