If someone tells you that the trade unions are the last protection for employees against a tyrannical elite/government, one is not telling you the truth, because the so called trade unions were setup by the system, for the system. The system has organized against the people (over a century now), against the employees. The trade unions are shields between the elite/gov and the employees (revolutionary branches of the system), in the same way as politics is the shield between the elite and the people. Look at the number of ways to lure the people on their side, or gain power of masses of employees by destroying the factories (sell outs, bail outs, merges, ending the old industry to cause an industry that is part of the system, it's about the employees, the numbers) Never choose the side of a tyrannical system, or the revolutinary branches (many) of the system, or the many other revolutionary groups and political parties (all not there for your advantage but of a ruling elite with an imperialistic agenda)
That wouldn't fit with the anarchist outlook where trade union success is the primary explanation for the shift in globalisation (and subsequent methods to ensure worker compliance)
Independent trade unions are not, and that's usually the type of unions defended by the left. Note; the US has almost no independent trade unions remaining, so citing examples like the AFL-CIO will not demonstrate your point.
