In 1917 the Socialist Revolutionaries split between those who supported the Provisional Government and the Bolsheviks who favoured a communist revolution. Those like Maria Spirdonova and Mikhail Kalinin who supported the revolution became known as Left Socialist Revolutionists (LSR)
After the October Revolution the LSR joined the in a coalition government with the Bolsheviks. However, the LSR left the government over their disagreement with Lenin over the signing of the Brest-Litovsk Treaty, the lack of freedom for trade unionists and the abandonment of the policy of workers' control of factories.
After the February Revolution, a former member of the SR, Alexander Kerensky, was appointed as Minister of Justice. Later, Victor Chernov entered the cabinet as Minister of Agriculture and Kerensky became prime minister.
The party strongly opposed the Bolsheviks during the October Revolution. In the elections held for the Constituent Assembly in November, 1917, the SR won 20,900,000 votes (58 per cent), whereas the Bolsheviks won only 9,023,963 votes (25 per cent).
In 1918 the Soviet government closed down the Constituent Assembly and banned the SR and other anti-Bolshevik parties. On 10th July the Soviet Commander at Simbirsk, a member of the Left Socialist-Revolutionaries, attempted to lead a uprising but it was soon defeated by the Red Army.
Some SRs now resorted to individual acts of terrorism. On 30th August, 1918, Vladimir Lenin was shot by Dora Kaplan and soon afterwards Moisei Uritsky, Commissar for Internal Affairs in the Northern Region, was assassinated by another supporter of the SR.
Next day the Congress met again. The Left S.R. delegates turned up. They had come to stage another violent onslaught on the Bolsheviks and the Government, the last, as it turned out, before they adopted other methods. The business of the morning was a report by the Chairman, Sverdlov, on the activities of the Government. He described in some detail the methods now being adopted to secure food from the villages in North and Central Russia. Committees of Poor Peasants had been formed in the villages to obtain food deliveries from the more well-to-do peasants.
"Leave it to the free peasants to form their own communes inspired with revolutionary enthusiasm,' cried Marie Spiridonova, that Valkyrie of the Russian Revolution. Pale, and with a savage look on her face, she proceeded to deliver an absolute Philippic against the Soviet Government and all its works. One realized now that, if this romantic revolutionary enthusiasm from the past could not be tamed, the Revolution would go down in chaos. When Spiridonova sat down, roars of applause came from the whole Left SR membership, the Bolsheviks sitting silent. Then the Left S.R.s all rose and left the Congress, this time for good. Sverdlov then adjourned the Congress till the afternoon.
The Revolution with extraordinary consistency brings to its logical end every one of its stages, mercilessly exposing the stupidity and credulity of those who use tactics unsuitable for a given situation. The Left S.R.s have committed political suicide by striking against revolutionary Realpolitik, just as the Mensheviks and Right S.R.s committed suicide last summer, by clinging to their coalition with the middle-classes long after the necessity for such a coalition had disappeared. Henceforth we. Bolsheviks, the spokesmen of the advance guard of the proletariate, must bear the sole burden of the Revolution.