Quarrels between the two factions dominated party politics until World War I.

Exile

Lenin spent most of the years until 1917 in exile in Europe. He returned to Russia after the peak of the 1905 Revolution, but the reaction that descended on the country in 1907 again forced him to flee abroad.

As he wandered through Europe, Lenin lived a hard, bitter existence. He exchanged recriminations with the Mensheviks about the Revolution's failure, and many of his most talented disciples deserted him. At this time he wrote his major philosophical tract, Materialism and Empirio- Criticism (1909). Three years later, at a party conference in Prague, the break between the Bolsheviks and the Mensheviks became final.
When World War I broke out in 1914, Lenin opposed it on the grounds that workers were fighting each other for the benefit of the bourgeoisie. Instead, he urged socialists "to transform the imperialist war into a civil war". He expounded and systematized Marxist views of the war in Imperialism, the Highest Stage of Capitalism (1917), arguing that only a revolution that destroyed capitalism could bring lasting peace.

Revolutionary Leader

The Revolution of March 1917 that overthrew the tsarist regime caught Lenin by surprise, but he managed to secure passage through Germany in a sealed train. His dramatic arrival in Petrograd (as St Petersburg had been renamed) occurred one month after rebellious workers and soldiers had toppled the tsar. The Petrograd Bolsheviks, including Joseph Stalin, had agreed with the deference the Soviet of Workers' and Soldiers' Deputies showed the bourgeois provisional government. Lenin immediately repudiated this line of policy. In his "April Theses" he argued that only the Soviet could respond to the hopes, aspirations, and needs of Russia's workers and peasants. Under the slogan "All Power to the Soviets", the Bolshevik party conference accepted Lenin's programme.

After an abortive workers' uprising in July, Lenin spent August and September 1917 in Finland, hiding from the provisional government. There, he formulated his concepts of a socialist government in a famous pamphlet, State and Revolution, his most important contribution to Marxist political theory. He also bombarded the party's Central Committee with demands for an armed uprising in the capital. His plan was finally accepted; it was put into effect on November 7.

Premises

A few days after the November Revolution, Lenin was elected chairman of the Council of People's Commissars, that is, head of government. He acted pragmatically to consolidate the power of the new Soviet state.