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).
Ukrainian People's Republic
After the Bolshevik Revolution of November 1917, many governments formed in Ukraine – most notably the Ukrainian People's Republic (based in Kiev) and the Ukrainian People's Republic of Soviets (1917–1918, based in Kharkiv) and its Soviet successors. These two entities, plus the White Movement, Poland, Green armies and the Revolutionary Insurrectionary Army of Ukraine, fought constantly with each other, which resulted in many casualties among Ukrainians fighting in a Ukrainian civil war (1917-1921) as part of the wider Russian Civil War of 1917-1922. The Soviet Union would (after the 1921 Treaty of Riga) extend control over what would ultimately become the Ukrainian Soviet Socialist Republic and (in 1922) a founding member of the Soviet Union.