Ukrainian Soviet Socialist Republic
Eventually, after the creation of the Communist Party (Bolshevik) of Ukraine in Moscow, a third Ukrainian Soviet government was formed on 21 December 1919 that initiated new hostilities against Ukrainian nationalists as they lost their military support from the defeated Central Powers. Eventually, the Red Army ended up controlling much of the Ukrainian territory after the Polish-Soviet Peace of Riga. On 30 December 1922, along with the Russian, Byelorussian, and Transcaucasian republics, the Ukrainian SSR was one of the founding members of the Union of Soviet Socialist Republics (USSR).
Eurasian Economic Union
Ukraine submitted an application to participate in the Eurasian Economic Union as an observer in August 2013. Viktor Yanukovych's decision to abandon an association agreement with the European Union and exclusively pursue integration with the EAEU was a key factor in the Euromaidan protests that ended his term as president of Ukraine and led to the Crimean Crisis. The country's membership in the EAEU was seen by some analysts as the key to the success of the union as Ukraine has the second largest economy of any of the 15 former republics of the Soviet Union. With high tensions between Russia and Ukraine in the wake of the crisis, Ukraine decided to pursue integration with the EU.