After the Mastricht Treaty, the future of the EEC social di-mension seems to be conditioned by contrasting factors. On the one hand, it appears to be endangered by the principie of («verti¬cal») subsidiariety, which, in some Authors' opinion, could lead to a lessening of the impact of the Comunity action in the social field. On the other hand, the possibilitíes recognized to collective bargaining by the Protocol on social policy could undermine the effects of the principie of subsidiariety («orizontal» subsidiariety). The Author locates the rooth of this ambiguity in a wrong ap-proach to EEC labour law and proposes to view subsidiariety from the standipoint of the balance of powers within the Commu-níty rather then from that of the relation between legal sources. This allows us to move the attention on to the issue of the demo-cratic legitimation of the structures where decisions on the EEC labour law are taken.