This article focuses on the new opportunity for the natio¬nal parliaments to get involved in the EU legislative process which is provided by the so-called yellow card mechanism introduced by the Lisbon Treaty. I start with a discussion of the incentives for na¬tional parliaments to seize the new opportunity to influence Europe¬an decision-making. I argue that the importance of the mechanism goes far beyond its stated goal to enforce the subsidiarity principle. Its true significance will first be in the engagement of parliaments in debates on the substantive issues of European policy, and second in stimulating cooperation amongst the parliaments of different Member States. In turn, this engagement and cooperation of parliaments can be expected to bring about communication among the citizens across national public spheres and their engagement with substantive policy issues rather than merely arguing for or against integration as is the case today. Thus, this modest-looking mechanism promises to nur¬ture a transnational network of public spheres and to become what may be called a demoi-cracy. I also argue that the creation of such a network democracy (post-national rather than supra-national) is the only available road for democratisation of the EU because it does not depend on a forged common identity or solidarity. In the final section, I discuss experience with the mechanism during its first year, which seems disappointing.