The Marxist-Leninist Party is the organizer and leader of the proletariat's class struggle. Stalin called the Party "the political leader of the working class." Karl Marx and Frederick Engels, in the "Communist Manifesto", theoretically substantiated the Marxist party's vanguard role. A Marxist-Leninist Party, the advanced, conscious and organized detachment of the working class, is capable of being the vanguard of the proletariat because it wields the weapon of Marxist-Leninist theory and applies it to the world. The highest form of proletarian class organization, the Party gives leadership to the working class' struggle and combines all of it's forms into an assault on capitalism. Without the leading vanguard role of a Marxist-Leninist Communist Party, socialism cannot be won.
Communists bring Communist consciousness to the working class and fight for the purity of the Marxist-Leninist world outlook. "The Party constantly develops the people's socialist consciousness and protects the working class from the influence of corrupting bourgeois ideology; the Party wages an implacable struggle against any attempt to falsify or 'revise' Marxism. It develops Marxist theory in the light of the latest scientific achievements and the practical experience of society." (V. Afanasyev, Marxist Philosophy)
From capitalism to socialism, the Marxist-Leninist Communist Party must be the vanguard of the working class. "By educating the workers' party," V.I. Lenin said, "Marxism educates the vanguard of the proletariat which is capable of assuming power and of leading the whole people to socialism, of directing and organizing the new order, of being the teacher, the guide, the leader of all toilers and exploited in the task of building up their social life without the bourgeoisie and against the bourgeoisie.' (Lenin, State and Revolution, 1917)
After the victory of socialism, as the great Communist William Z. Foster pointed out, "the leader and organizer of the proletarian dictatorship is the Communist Party." (William Z. Foster, Toward Soviet America, 1932)