In the imperialist epoch, therefore, the very basis of union action is modified, which, in critical periods, quickly transcends to either an insurrectionary struggle or to a total sacrifice of working-class conditions. But this also means that a union led by any party other than the revolutionary class party cannot in these critical periods conduct the economic struggle in a consistent manner, which was possible in the epoch of the “peaceful” development of capital. In that epoch the economic struggles of the proletariat could also oppose the revolutionary struggle, as they can at present in non-critical epochs, but in the imperialist epoch the connection is tighter.
[…]
From this union dynamic of the imperialist epoch, some pseudo-revolutionaries have deduced that the time of union demands and workers’ defense organizations is over, and that nothing can be conceived now, in terms of struggle against the system, that is not immediately and exquisitely political, denouncing the struggles for economic defense as backward, internal to the system, or even reactionary or corporatist, joining in this judgment with the official opportunists. Others, who also claim to refer to the Communist Left, have deduced that the resurgence of intermediate bodies between the Party and the class can be configured according to an original process, not foreseen in our bodies of theses, whereby these bodies can also have immediately political content, skipping the economic phase. Such conceptions automatically place those who support them outside the field of revolutionary Marxism and historical materialism, and reunite them with idealism, for which men would be driven to act not by immediate economic conditions, but by ideological and political concepts, even if acquired on the field of class struggle.
The observation that in an imperialist regime the consequent defense of the economic interests of the class is drastically and categorically incompatible with the stability of the capitalist system and therefore immediately assumes a subversive content which is intolerable for the bourgeois institutions leads, on the contrary, to the confirmation that future class organizations can only originate from the battle for the desperate defense of the living conditions of the working masses, and therefore can only have an immediate content which is essentially economic.
[…]
In order to decide whether or not to work in a trade union, therefore, it’s not enough to identify the historical tendencies of the trade union form and verify which are attributable to the organization in question. That is, it is not enough to deduce the tactics from the political nature of this body, but it’s necessary above all to see the attitude of the workers towards it. As materialists we cannot attribute to the workers enrolled in a union the consciousness of what it historically represents to Marxist investigation. If the workers, or the majority of them, the most combative ones, see in a given union their representative, the instrument for their defense, and fight for it and with it, our place of battle can only be in that union.
"The Party Facing the Trade Unions in the Age of Imperialism" - from Comunismo no. 10, the publication of the International Communist Party (excerpts of Ch. 8), 1982