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).
Post-Soviet states
Russia, Belarus, Kazakhstan created a customs union that entered into force in July 2010. Ukraine, Kyrgyzstan and Tajikistan indicated interest in joining at the time. Russia has been eager for Armenia, Moldova and Ukraine to join the custom union instead of the European Union, and the Moldovan break-away state of Transnistria has supported this. In 2013, Kyrgyzstan and Armenia announced plans to seek membership, but division over the issue in Ukraine led to the 2014 Ukrainian revolution after the Ukrainian government backed out of an EU Eastern Partnership in favor of the union. In 2014, voters in the Moldovan autonomous region of Gagauzia rejected closer ties to the EU in favor of the union.