After the February Revolution of 1917, Dashnaktsutyun had become more active, growing into a serious political force in the region. Following the October coup, the Dashnaks together with the Georgian Social Democrats and Musavatists opposed the Bolsheviks, demanding the separation of Transcaucasia from Soviet Russia. Party members participated in the organization of the Transcaucasian Commissariat (November 1917) and the operation of the Transcaucasian Seim (February – May 1918). In May 1918 – November 1920, the Dashnaktsutyun leaders (Hovhannes Kajaznuni, Aleksander Khatisian, Hamazasp Ohanjanyan, Simon Vratsian) were at various times the chairmen of the government of the Republic of Armenia, and the Dashnak faction had an absolute majority (90 %) in the country’s parliament. Territorial claims of the Dashnaks became one of the causes of the Armenian-Georgian (1918) and Armenian-Azerbaijani (1919–1920) armed conflicts.
At the end of March 1918, in Baku, the Dashnaks supported the local Soviet of Workers’ and Soldiers’ Deputies (the Baku Commune) in its struggle against representatives of the Muslim party Musavat, having organized pogroms among the Muslim population. July 25, 1918, at a meeting of the Baku Council, with the participation of the Dashnaks, a decision was made to invite British troops to Baku.
The Party had organizations in the Turkestan Autonomous Socialist Soviet Republic, where it connected with the Armenian communities, after uniting with the Bolsheviks of the region. In the Ferghana Valley, the Dashnaks participated in pogroms of Muslims (also, after the fall of the Kokand autonomy), which led to their clashes with the Basmachi. In the period from 1918 to mid-1919, the Soviets of Andijan were under the control of the Dashnaks.
In the fall of 1920, the Dashnaks who headed the Republic of Armenia, dragged the country into a war with Turkey aiming to annex its six eastern vilayets (provinces). Turkey won the conflict, occupying a significant part of the Armenian lands. With this military defeat, by the end of 1920, the Dashnaks lost control of the situation in the country. Soviet power was established in most of the territory of Armenia. After that, some Dashnak leaders were subjected to repression, while the rest fled to Zangezur (south-eastern Armenia) and in December 1920, announced the creation of the Autonomous Syunik Republic. In Georgia, leaders of the third group of Dashnaks created a Motherland Salvation Committee that received assistance from the Democratic Republic of Georgia, Great Britain, the United States and organized an uprising against the Soviet government, as a result of which Erivan (Yerevan) was taken over on February 18, 1921. The Committee declared itself the government. Simon Vratsian became the last Prime Minister of the Republic of Armenia.
After the Workers’ and Peasants’ Red Army had successfully completed the Erivan operation (March–April 1921) and Soviet power had been restored, the Dashnak leaders fled from Erivan to Zangezur and headed the government of the Republic of Nagorno-Armenia (proclaimed on April 26, 1921).
In July 1921, under the onslaught of the Red Army, the Dashnaks were forced to leave the territory of Armenia, where their activities were subsequently banned. In the 1920s, Dashnaktsutyun members established organizations in the United States, Europe, and the Middle East. The party has been operating in Armenia again since the late 1980s and actively participates in the country’s political life.