It is necessary to bear in mind that the great Marxists of the late 19th and first decades of the 20th century were writing about unions which, notwithstanding their severe limitations, played a far greater role in the daily life of the working class than the moribund trade union organizations of today. The pre-World War I German unions, in particular, provided many social services and served as a center of the cultural life of the workers. Officially, at least, they championed the socialist aspirations of the working class, and masses of workers looked to them for leadership and participated in their activities. Those who led the mass German unions had been initially educated and trained by the party and claimed the mantle of Marxism.
Even in the first decades following the Second World War, the major unions in Europe claimed some form of allegiance to socialism, and the AFL-CIO in the US remained, to some extent, a focus of the militant resistance of workers to the encroachments of big business. It was one thing, under these conditions, for the revolutionary party to employ as a central tactic the placing of demands on the union leadership, as a means of exposing the trade union bureaucracy before the workers. It is an entirely different matter today, after two decades during which the unions have essentially completed their degeneration, betraying the most elementary interests of the working class and transforming themselves into outright corporatist extensions of the employers and the state.
In an article written in 1937 entitled “Not a Workers’ and Not a Bourgeois State?” Trotsky answered those who argued that the crimes of the Stalinist bureaucracy and its totalitarian methods rendered the Fourth International’s characterization of the Soviet Union as a degenerated workers’ state obsolete. “The class character of the state is determined by its relation to the forms of property in the means of production,” he wrote. Insofar, therefore, that the Soviet regime continued to base itself on the nationalized property forms established by the October Revolution, it remained a workers’ state. At the same time Trotsky insisted that this assessment was not timeless. Unless the horrific degeneration of the Soviet state was halted, through a political revolution of the Soviet working class and the overthrow of the Stalin regime, and the Kremlin’s nationalist program was replaced by the international revolutionary program of Bolshevism, the bureaucracy would inevitably complete its counterrevolutionary role and usher in the restoration of capitalism.
To illustrate his basic point, Trotsky made an analogy to the trade unions. “The character of a workers’ organization such as a trade union is determined by its relation to the distribution of national income. The fact that [AFL President] Green and Company defend private property in the means of production characterizes them as bourgeois. Should these gentlemen in addition defend the income of the bourgeoisie from attacks on the part of the workers; should they conduct a struggle against strikes, against the raising of wages, against help to the unemployed, then we would have an organization of scabs, and not a trade union.” 
If one considers the role of the AFL-CIO and its international counterparts in the more recent period, in light of Trotsky’s stipulation that a trade union is a workers’ organization insofar as it seeks to defend the workers’ share of the national income, then it is clear these organizations have, for some time, failed to meet this criterion. For an extended period, the AFL-CIO has actively collaborated with the bourgeoisie in lowering the living standards of the working class, sabotaging strikes, framing up workers and throwing workers onto the unemployment lines. More recently, it has embraced the government’s forced-work welfare “reform,” by which the ruling class seeks to turn millions of unemployed into a new source of super-exploited cheap labor.
Workers are trapped inside “trade union” organizations, which have assumed the character of corporatist syndicates, controlled by petty-bourgeois bureaucracies, whose own interests are in no way connected to even a residual defense of the rank and file’s share of the national income.
Trotsky, Writings 1937-38, New York, Pathfinder, p. 65