Bolshevism, Communist doctrine based on the theories of Karl Marx as formulated by Lenin. These theories were outlined at the second congress of the Russian Social Democratic Labor party held in London in 1903. The divergent viewpoints of the delegates to the congress crystallized into two factions, the more radical faction being led by Lenin. He advocated a unified party of active, professional revolutionary members, willing to use any means to establish a Communist society.

His opponents, on the other hand, proposed to admit all who declared general sympathy with the aims of the party, regardless of active participation. On this point the congress supported the latter plan, but on other matters and in the final vote that elected the party leadership, the congress favored Lenin. The faction led by Lenin was thereupon called Bolshevik (from the Russian word for “majority”), and the opposition, Menshevik (from the Russian word for “minority”). The names clung, although the Bolsheviks were not always thereafter the dominant group in the Russian revolutionary movement.

Factional Differences The essential differences between the Bolsheviks and the Mensheviks appeared more clearly in subsequent years, when an apparent agreement on a Marxist program—the overthrow of czarism, the establishment of constitutional government, and, finally, the overthrow of capitalism and the establishment of a Communist society—resulted in wide variations in practice. The Bolsheviks supported the immediate objectives only insofar as they led in the direction of the final revolutionary aim. The Mensheviks, however, believing that Russia was not ready for revolution, placed the emphasis on reform, especially the establishment of constitutional government. Neither faction played a dominant role in the revolution that followed the defeat of Russia in the war with Japan in 1905.


The workers’ soviets (legislative bodies) were formed spontaneously, and Lenin failed at first to realize their importance. Leon Trotsky, who, as chairman of the St. Petersburg Soviet, was the active leader of their revolution, was neither Bolshevik nor Menshevik, but stood between the two factions, striving to unite them. When, as a result of the revolution, a parliament, called the Duma, was established later in 1905, the Bolsheviks preferred at times to boycott it and at other times used it as a forum from which to agitate, whereas the Mensheviks hoped to build the strength of the anticzarists within it.

The Split into Two Parties

As a result of increasing differences, a final split between the two factions occurred in 1912. Thereafter the two parties, together with others, competed for the leadership of the anticzarist revolution. The Bolsheviks used both legal and underground tactics to advance their program, building a membership, in accordance with Lenin’s original specifications, of about 45,000 by March 1917, and 240,000 by July of that year. The Bolsheviks opposed World War I as an imperialist conflict in which socialists should have no part, but the Mensheviks and Social Revolutionaries, placing national before class interests, supported and eventually attempted to take leadership in the Russian war effort. As a result of the collapse of the Russian armies and the growing awareness of the inefficiency of the government, a revolution broke out in March 1917, resulting in the abdication of the czar and the introduction of parliamentary government. The provisional government, which included Mensheviks, was charged by the Bolsheviks with an unwillingness to expand the revolution in the direction of socialism. The Bolsheviks undertook this task through the soviets of workers and soldiers. The Bolsheviks seized state power in November 1917. In 1918, under the new name of the Communist (Bolshevik) party adopted from an earlier organization led by Marx, they began their career as the dominant, and later, by decree, the sole political organization in the USSR. The subsequent history of the theory and practice of bolshevism is indistinguishable from that of communism.