The Mensheviks
The Mensheviks were a “sister party” to the Bolsheviks. Both parties emerged as a result of the 1903 split in the Russian Social-Democratic Labor Party (RSDLP). Over the period between the split and the February Revolution, there were a number of projects aimed at unifying the two parties, which ultimately weren’t successful.
The Mensheviks took a more moderate social democratic position compared to the Bolsheviks; they engaged in overt political action, participated in the work of the State Duma and advocated the continuation of the war. In their ideology and structure, the Mensheviks very much resembled the European social democratic parties.