In February 1918, Proshian and Karelin together with Vladimir Lenin, Leon Trotsky, and Joseph Stalin formed the SNK Executive Committee of the Russian SFSR. From January to July 1918, Maria Spiridonova headed the Peasant Section of the VTSIK. The PLSR representatives were also members of the Supreme Military Council, the Supreme Board of the National Economy, regional Soviet governments, held the positions of Deputy People’s Commissars and members of the boards of People’s Commissariats, responsible posts in the All-Russian Extraordinary Commission (VChK), in the navy, commanded formations and fronts of the Workers’ and Peasants’ Red Army (Mikhail Muravyov, Aleksander Egorov and others).

 

After some hesitation, the PLSR supported the Bolsheviks on the issue of dissolving the Constituent Assembly. At the 3rd All-Russian Congress of Soviets (January 1918), the approval of the first section of the Fundamental Law of Land Socialization that was developed by the left SRs was an indicator of close cooperation between the two parties. Representatives of the PLSR participated in the drafting of the Constitution of the 1918 Russian SFSR.

 

In June 1918, the Ukrainian Party of the Left SRs was formed, at the end of the year, the Party of the Left SRS of Lithuania and Belarus. The party reached its maximum of 150 thousand people (June 1918). In fact, the PLSR had become the second most influential party in Soviet Russia.

 

Opposed by the majority of PLSR leaders, the Treaty of Brest-Litovsk was the first issue that caused serious disagreements between the Left SRs and the Bolsheviks. In March 1918, the Left SRs left the government but remained in the leadership of the Soviets at all levels, as well as in the boards of People’s Commissariats and the regional Soviet governments. In April, they became part of the Bureau for the Leadership of the Insurgent Struggle in the Ukraine territory occupied by Germany and Austria-Hungary (the “Rebel Nine”).

 

In May–June 1918, a confrontation between the Left SRs and the Bolsheviks broke out over the emergency food policy: at the meetings of the All-Russian Central Executive Committee, representatives of the Left SR faction opposed the adoption of decrees on the food dictatorship and the committees of the rural poor.

 

By the time of the convocation of the 5th All-Russian Congress of Soviets (July 4), the contradictions between the two parties had reached a critical point. On June 24, 1918, the Central Committee of the PLSR confirmed the decision taken at the 2nd Party Congress (April 1918) – to put an end to the peaceful “respite” by organizing a number of terrorist acts against German diplomats. The 3rd Congress of the PLSR (June 28 – July 1, 1918) called for the transfer of full power to the All-Russian Central Executive Committee of Soviets and the abolition of the Russian SFSR SNK and authorized the disruption of the Treaty of Brest-Litovsk.

 

On July 6, 1918, members of the PLSR assassinated the German ambassador Count Wilhelm von Mirbach. Maria Spiridonova tried to convince the 5th Congress of Soviets of the need to resume the revolutionary war with Germany. The Bolsheviks arrested the entire Left Socialist Revolutionary faction of the Congress of Soviets. In response, the Left SRs arrested the VChK chairman Felix Dzerzhinsky and some other Bolsheviks, occupied the Central Telegraph Office, and began agitation in the troops of the Moscow garrison in support of the coup. The Bolsheviks accused the Left SRs of an anti-Soviet rebellion and quickly took control of the situation. The attempt made on July 10, 1918, by the commander-in-chief of the Eastern Front of the Red Army, Mikhail Muravyov, to stage a coup in Simbirsk (it is unclear whether he acted with the sanction of the PLSR) also failed with him being killed.

 

After July 6, 1918, the Left Social Revolutionaries lost their representation in the All-Russian Central Executive Committee and local Soviets. Part of the party supported the tactics of the Central Committee, while the other supported a united revolutionary front with the Bolsheviks (in September 1918, supporters of this position formed the Party of Narodnik Communists and the Party of Revolutionary Communism). The 4th Congress of the PLSR (October 1918) dissociated itself from the groups that had left the party, condemned the dictatorship of the Bolshevik Party and its conciliatory policy towards Germany. It called for the restoration of freely elected Soviets and armed support for the uprising in Ukraine. Under the agitation of the Left Social Revolutionaries in February 1919, strikes were held at several enterprises. In response to that, mass arrests of party members took place.

 

Under these conditions, some of the Left SRs advocated an active struggle against the “commissar autocracy”. ”Activists” supported peasant anti-Bolshevik uprisings, joined the Green movements. They were among those who organized the explosion in the premises of the Moscow Committee of the Russian Communist Party (Bolsheviks) – RCP (b) on September 25, 1919. Some of the left SRs leaned towards anarcho-syndicalism, several party members joined Nestor Makhno.

 

However, the PLSR leadership had a dominating number of those who wanted to preserve the legal status of the party in the Russian SFSR (”Legalists“) and who abandoned the armed struggle against the RCP(b). At the All-Russian Conference (December 1920), this part of the Left SRs formed the United PLSR (syndicalists and internationalists), which participated in the work of the 8th All-Russian Congress of Soviets (December 1920), the elections to the Soviets (spring 1921), etc.

 

After the Kronstadt Rebellion (March 1921), the repressions against the Left SRs became a regular thing. By the mid-1920s, almost all the Left SR leaders and activists were in prison and exile. The foreign delegation of the PLSR continued to exist until 1930.