The history of the workers’ movement begins with the unions, the basic organisation of the class which were “not only a natural, but also an essential phenomenon under capitalism and… an extremely important means for organising the working class in its daily struggle against capital and for the abolition of wage-labour”. But once established, the trade unions cannot confine their sphere of activity to economic demands, but inevitably tend to move into the political plane. Here, what is involved is not the sporadic struggles of individual groups of workers against their employers, but the struggle of the proletariat as a whole against the bourgeoisie as a class, and its state.
The trade unions are the basic organisations of the working class. But they are much more than that. They are the embryo of the future society within the old. Of course, since the workers’ organisations exist in capitalist society, they are subjected to alien class pressures. These pressures weigh heavily on the upper stratum and this often leads to degeneration. We are not dealing with an ideal norm, but with the mass organisations as they really exist in class society. The distortions that occur, especially in periods when the working class is not on the move, can produce a feeling that the unions cannot be changed. This is a serious mistake that is contradicted by the whole historical experience of the movement. Time and again the workers have moved to transform their organisations into organs and schools of solidarity, struggle and socialism, to use the phrase of Frederick Engels.
As Trotsky explains in the The Transitional Program for Socialist Revolution  (written in 1938):
"In the struggle for partial and transitional demands, the workers now more than ever before need mass organizations, principally trade unions. The powerful growth of trade unionism in France and the United States is the best refutation of the preachments of those ultra-left doctrinaires who have been teaching that trade unions have “outlived their usefulness.”
"The Bolshevik-Leninist stands in the front-line trenches of all kinds of struggles, even when they involve only the most modest material interests or democratic rights of the working class. He takes active part in mass trade unions for the purpose of strengthening them and raising their spirit of militancy. He fights uncompromisingly against any attempt to subordinate the unions to the bourgeois state and bind the proletariat to “compulsory arbitration” and every other form of police guardianship – not only fascist but also “democratic.” Only on the basis of such work within the trade unions is successful struggle possible against the reformists, including those of the Stalinist bureaucracy. Sectarian attempts to build or preserve small “revolutionary” unions, as a second edition of the party, signify in actuality the renouncing of the struggle for leadership of the working class. It is necessary to establish this firm rule: self-isolation of the capitulationist variety from mass trade unions, which is tantamount to a betrayal of the revolution, is incompatible with membership in the Fourth International.
"At the same time, the Fourth International resolutely rejects and condemns trade union fetishism, equally characteristic of trade unionists and syndicalists.
"(a) Trade unions do not offer, and in line with their task, composition. and manner of recruiting membership, cannot offer a finished revolutionary program; in consequence, they cannot replace the party. The building of national revolutionary parties as sections of the Fourth International is the central task of the transitional epoch.
"(b) Trade unions, even the most powerful, embrace no more than 20 to 25 percent of the working class [In the USA today, they make up only 13 percent – Editor], and at that, predominantly the more skilled and better paid layers. The more oppressed majority of the working class is drawn only episodically into the struggle, during a period of exceptional upsurges in the labor movement. During such moments it is necessary to create organizations ad hoc, embracing the whole fighting mass: strike committees, factory committees, and finally, soviets [democratically elected committees of workers, soldiers, and peasants – Editor].
"(c) As organizations expressive of the top layers of the proletariat, trade unions, as witnessed by all past historical experience, including the fresh experience of the anarcho-syndicalist unions in Spain, developed powerful tendencies toward compromise with the bourgeois-democratic regime. In periods of acute class struggle, the leading bodies of the trade unions aim to become masters of the mass movement in order to render it harmless. This is already occurring during the period of simple strikes, especially in the case of the mass sit-down strikes which shake the principle of bourgeois property. In time of war or revolution, when the bourgeoisie is plunged into exceptional difficulties, trade union leaders usually become bourgeois ministers.
"Therefore, the sections of the Fourth International should always strive not only to renew the top leadership of the trade unions, boldly and resolutely in critical moments advancing new militant leaders in place of routine functionaries and careerists, but also to create in all possible instances independent militant organizations corresponding more closely to the tasks of mass struggle against bourgeois society; and, if necessary, not flinching even in the face of a direct break with the conservative apparatus of the trade unions. If it be criminal to turn one’s back on mass organizations for the sake of fostering sectarian factions, it is no less so passively to tolerate subordination of the revolutionary mass movement to the control of openly reactionary or disguised conservative (”progressive”) bureaucratic cliques. Trade unions are not ends in themselves; they are but means along the road to proletarian revolution."
Recommended further reading:
- Trade Unions in the Transitional Epoch  – By Leon Trotsky
- Should Revolutionaries Work in Reactionary Trade Unions?  – By VI Lenin
- The Trade Unions  – By Frederick Engels
- Trade Unions in the Epoch of Imperialist Decay  – By Leon Trotsky
- In the Cause of Labour – A History of British Trade Unionism  – By Rob Sewell