Czechs in Ukraine Mostly, they were women with ethnic Ukrainian husbands. Some others stayed of their own choice. During the Soviet era, they were one of the most affected groups by the Chernobyl nuclear power plant disaster in 1986. At the end of the 1980s, ten thousand Czechs lived in Ukraine. At the beginning of the 90s Czechoslovakia invited these remaining Czechs to return to the Czech Republic, which in 1993 almost 2,000 people did, and other people came to the Czech Republic in later years. As of today, Volhynian Czechs are still migrating. In 2014, after the revolution in Ukraine and the
Russian military intervention in Ukraine (2014–present) sphere of interest. Iulian Chifu and his co-authors claim that in regard to Ukraine, Russia pursues a modernized version of the Brezhnev Doctrine on "limited sovereignty", which dictates that the sovereignty of Ukraine cannot be larger than that of the Warsaw Pact prior to the demise of the Soviet sphere of influence. This claim is based on statements of Russian leaders that possible integration of Ukraine into NATO would jeopardize Russia's national security. After the collapse of the Soviet Union, both nations retained very close ties. At the same time, there were several sticking points, most importantly Ukraine's significant nuclear