The current financial crisis coincides with a period of deep political and substantive crises in the European Union. Although it is difficult to predict how it will affect the further development of the EU, it has certainly revealed the full range of the challenges which the EU is facing - both in terms of its political system and its policies. On one hand, the crisis has shown that some Member States are inclined to work in smaller groups, perhaps at the cost of the Union's cohesion. On the other hand, it has also demonstrated that the EU is attractive and that the Member States perceive it as an effective mechanism to guarantee their financial, economic and political security. At the same time, the financial crisis has definitely increased public awareness in the Member States of the need to increase the effectiveness of the EU and thus to complete the political reform, discussed for years, by putting the Treaty of Lisbon into effect. Thus, the greatest remaining challenge is to maintain the coherence of the process of European integration. While the entry into force of the Treaty of Lisbon gives the EU new momentum in this respect, it does not guarantee success - strengthening the effectiveness of the EU. Much will depend on the measures used to implement the reforms prescribed by the Treaty, which are aimed at providing regulation of the relations between the EU and its Member States in managing common issues. In the end, the decisive factor will be the political will of the Member States to use the new opportunities offered by the Treaty of Lisbon to increase the effectiveness and cohesion of the EU.