Lenin's theory of the party, developed in his 1902 work *What Is to Be Done?*, posited that the working class could only develop 'trade union consciousness' on its own and needed a highly disciplined, centralized party of professional revolutionaries to bring it socialist consciousness[citation:3][citation:7]. This 'party of a new type' would serve as mentor and guide, organizing the proletariat to overthrow the existing order[citation:4]. This model became the blueprint for Communist parties worldwide after the Russian Revolution.

The Mensheviks, following orthodox Marxists like Plekhanov, argued that Russia's bourgeois revolution must be led by the bourgeoisie, with the proletariat acting as a junior partner. Lenin defiantly rejected this, declaring the proletariat must lead an alliance with the peasantry to establish a 'revolutionary democratic dictatorship of the proletariat and the peasantry'[citation:4]. This strategic difference became the defining split between the Bolsheviks and Mensheviks.

Lenin argued that capitalism had entered a new 'imperialist' phase characterized by monopoly, finance capital, and the division of the world into oppressor and oppressed nations[citation:2][citation:10]. This theory explained why revolutions had not yet occurred in the West and justified the attempt at socialist revolution in Russia. It also provided a strategic framework for allying with national liberation movements against imperialist powers[citation:5].

Lenin led the Bolshevik seizure of power in the October Revolution of 1917, becoming the architect and first head of the Soviet state[citation:1][citation:8]. He signed the Treaty of Brest-Litovsk to end Russia's involvement in World War I, repulsed counterrevolutionary forces in the Civil War, and founded the Third (Communist) International in 1919[citation:5][citation:12]. Facing economic collapse, he introduced the pragmatic New Economic Policy (NEP) in 1921, which permitted a measure of private enterprise.

Yes, in his final years Lenin became deeply concerned about what he saw as the degeneration of the Soviet system and the party. He criticized Stalin for concentrating power and for his 'Great Russian chauvinism' toward non-Russian nationalities[citation:5]. In his political 'Testament,' dictated in late 1923, he expressed fear for the stability of the party under the leadership of forceful personalities like Stalin and Trotsky, though he was unable to prevent Stalin's rise before his death[citation:5].