There are voices that the EU faces a dilemma of effectiveness vs. democracy of the decision-making processes. Therefore, it is necessary to make a compromising system of the EU law that would enable a precise guarantee of the primary freedom and rights and at the same time, the law that is flexible enough to allow a further development of the integrative processes while maintaining an effective decisionmaking process. These conditions are fulfilled by the EU cooperation based on the subsidiarity principle and the partnership principle. One of the subsidiarity most important assumption is the transition of the decision-making situation to the level that is as close to the citizens as it is possible and to the level of the nation state in case of difficulties in competence assignment. Next, the partnership allows the non-public authorities to take part in the decision-making system. But at the same time both principles leave much freedom and competence to the EU structures so that they are able to guarantee the achievement of objectives and tasks of the integration body. What is more, the complexity of decisive processes in the European Union as well as multitude of issues regulated by it has led to a situation in which we can observe a sudden increase in – for example – regional and local authorities involvement, whose importance for the EU is still growing. The article below constitutes a contribution to the discussion about the definitions of the region, its meaning for the European Union’s decisional system and the prospects for the future.