[a] The UNR refused to recognize the newly installed Soviet government, which in turn caused a tension within the Central Rada.
The Bolsheviks faction convened an All-Ukrainian Congress of Workers', Soldiers', and Peasants' Soviets in Kyiv in December demanding recognition of Sovnarkom from the Central Rada.
After the July 6, 1918, assassination in Moscow of the German Ambassador to Russia Count Mirbach, many Bolsheviks who resented the terms of the peace treaty began guerrilla warfare and terror with support from Felix Dzerzhinsky, the head of the Cheka.
The Congress of Free Hubb'andmen on April 29, 1918 (with the great support of Austrian-German occupants), elected tsarist general P.P.Skoropadsky as Hetman of Ukraine.
He proclaimed the overthrow of the Central Rada Government thus suspending the UNR and also outlawed the Communist Party in Ukraine.
The Bolsheviks amid fluid alliances with various anarchists would eventually defeat the Ukrainian army that was fighting on several fronts simultaneously.
The ZUNR formally (and largely symbolically) joined the UNR in hope to gain some support in the war against Poland.
UNR forces fared poorly during Polish-Soviet War and a late alliance with Poland wasn't enough to secure the republic.
Canadian scholar Orest Subtelny provides a context from the long span of European history: Outside powers acted on entirely different visions for Ukraine.
Russian Bolsheviks did not believe in nationalism and twice invaded Ukraine and failed efforts to seize control and collectivize the farms; they succeeded the third time in 1920.