Employing a multidimensional conception of power shows how interaction between EU institutional actors is structured by different kinds of power – coercive, institutional and ideational – and that none of these are sufficient on their own for actors to successfully drive the reform process. We ask not just who leads the euro zone, but how interactions between actors enable the polity to achieve (or not) its goals. This requires thinking of power in terms of both zero-sum and positive-sum outcomes, which reveals the weakness of the polity as a whole, whatever the power of different institutional actors. In this view, key for the long-term sustainability of the euro zone is an economic and political rebalancing among its members borne out at the level of common ideas and institutions and the leadership of the most resourceful member states. Despite significant reforms in wake of the crisis, such rebalancing seems far beyond the horizon.