The present paper discusses the concept of solidarity in the Dublin System for determining the State responsible for examining an application for asylum in the EU. This case is especially critical because the Dublin System has given rise to sharp conflicts pertaining to interstate solidarity. It is only at first glance paradoxical that the non-hierarchical, cooperative idea of mutual solidarity is being called upon just at the moment that EU Member States have integrated themselves even further into the hierarchical framework of a quasi-federal structure with the Treaty of Lisbon. Solidarity in EU law aims to compensate an unequal distribution of costs and benefits caused by measures taken on the path to furthering supranational integration. The increasing demand for interstate solidarity is a natural corollary of the process of transitioning to a federation or, as Habermas put it, the anticipation of new political forms of integration.