To add my tuppenceworth ...
I would highlight Lenin’s insistence that the spontaneous thoughts of the masses are not immediately class consciousness. In this he follows in the enlightenment tradition, borrowing from the distinction that (Hegel says) Rousseau makes between the Many Wills and the General Will. Borrowing some terminology from the German idealists, he distinguishes between the Class in itself and the Class for itself (though I think to see the point through, it is not really a class at all without consciousness of itself, but something more like a rabble – or multitude). In Lenin’s mind the case for the party (a party of a new type, he says, not a bourgeois political party, but a party that aims ultimately to abolish the separation of politics and civil society) ... the case for the revolutionary party is to overcome the one-sidedness of spontaneous class consciousness. He does not say, as he was assumed to both by critics and some who thought they were acting on Lenin’s principles, that the party owns the truth. He was saying that the party should aspire to give expression to the highest level of consciousness, and seek to win over the people. He finessed that point by saying that it is not easy to address everyone all at once, but that the party would concentrate on influencing the most militant, the natural leaders of the class, the vanguard, and through them, influence the wider mass. I don’t say any of those conditions necessarily obtain today, only that that was what Lenin was saying (at least in my paraphrase).
His other specific intervention was on the question of the growing influence of reformism, illusions in the progressive role of the state, and what came with it, the subordination of internationalism to nationalism. All of this was, he thought, made possible because of the way that the imperialism of the more decrepit capitalist powers, gave them a kind of fund to subsidise some small reforms that tended to corrupt the workers’ movement along reformist lines. (This complaint strikes us all the more uncanny today, since most leftism is *nothing but* illusions in the progressive character of the state.)
To the lasting irritation of the contributors to Platypus he did more or less say that you were obliged to support the anti-imperialists who were at war with your own state (In ‘Nascent Trends of Imperialist Economism’).
His critique of reformism, then, was closely tied to his view that capitalism had entered a broadly degenerate stage, where its past progressive side was weaker, relative to its destructive side. His analysis of ‘imperialism’ sees the political movement to colonise the world as largely an effect of the degenerate character of capitalism, its descent into ‘coupon-clipping’ foreign investments, the coalescence of the state and capitalism, monopolies, merging of financial institutions and industry.
His Capitalist Development in Russia was important, too. There he used Marx’s elaboration of the way that capitalist investment does not only produce more than it consumes (as the populists claimed) but also creates an additional demand for goods in the form of means of production, and, for that reason, the immediate crisis that the Sisimondians imagined would stop capitalism ever taking off, would be mitigated (cf. Capitalist Development in China).
In his debates with the Narodniks he criticised Romantic anti-capitalism.