It's quite clear that Lenin's view of the role of a revolutionary socialist party was a significant deviation from anything that Marx wrote. My understanding of Marx's writings is that he never wished for some vanguard party to "take over" the state in the way that the Bolsheviks did, what with the emancipation of the proletariat being the work of the proletariat itself and and all that. However, I'm having a difficult time figuring out what role it is that Marx did favor such parties playing. In his Critique of the Gotha Program, he explicitly criticizes the reformism of that program. But, even if it had adopted different positions in its program, how else could the SPD have functioned? Surely its reformism was an inevitable outcome of its engagement in the arena of bourgeois politics rather than something that could have been avoided by adopting a different political program?
Did Marx view the party primarily as a useful tool for unifying revolutionary proletarian struggles and agitating for social revolution, something like what I think Rosa Luxemburg describes in Leninism or Marxism, rather than a "standard" political party? And if so, how does the engagement in parliamentary politics, the passage of legislation and so forth, fit in with this? What is the relation between parliamentary struggle and extraparliamentary struggle in terms of the role of a revolutionary socialist party?
All clarification is much appreciated.



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I'm no expert on this, but I think his views changed throughout his life. Circa the Communist Manifesto, there's an explicit aim to "win the battle of democracy", seeming to assume universal suffrage would bring a communist party to power. Other times, he seems to use 'party' more in the sense of 'party to a contract' rather than 'political party'.