But there's a caveat:
Just efforts to secure the rights of workers who are united by the same profession should always take into account the limitations imposed by the general economic situation of the country. Union demands cannot be turned into a... kind of group or class ‘egoism,’ although they can and should also aim at correcting — with a... view to the common good of the whole of society — everything defective in the system of ownership of the means of production or in the way these are managed. Social and socioeconomic life is certainly like a system of ‘connected vessels,’ and every social activity directed towards safeguarding the rights of particular groups should adapt itself to this system.
In this sense, union activity undoubtedly enters the field of politics, understood as prudent concern for the common good. However, the role of unions is not to ‘play politics’ in the sense that the expression is commonly understood today. Unions do not have the character of political parties struggling for power; they should not be subjected to the decision of political parties or have too close links with them. In fact, in such a situation they easily lose contact with their specific role, which is to secure the just rights of workers within the framework of the common good of the whole of society; instead they become an instrument used for other purposes. - John Paul II, Laborem exercens