The corona virus pandemic poses an unexpected challenge to the European Union and its Member States. It is part of the public debate on the direction of the Union’s institutional development – the Union may both strengthen cooperation and may begin to dominate centrifugal tendencies. Both the Community assistance program and the position on the “communitarisation” of planned debts will be of particular importance. On May 5, 2020, the Federal Constitutional Court of the Federal Republic of Germany issued a judgement, the essence of which is to question the binding force of the judgment of the EU CJEU in Germany. We have dealt with similar decisions in the case of the Spanish Supreme Court. The German ruling in particular will be of particular importance as regards the relationship between EU law and the constitutional law of the member states. In the article, the author discusses the most important rulings of the Polish Constitutional Tribunal to date and the resulting conclusions, including the obligation to provide a pro-EU interpretation of the Constitution of the Republic of Poland. The subject of the considerations was also the traditional understanding of state sovereignty and the need to verify it nowadays, which in fact has been taking place since the middle of the 20th century. The development of the EU will be the most important factor in its modern understanding. The author emphasized the key importance of two factors: the need to strictly adhere to the principle of subsidiarity in order to limit the EU’s regulatory tendencies and – on the other hand – the requirement to take the EU order (acquis communaitaire) into account in the interpretation and application of national law, including the Constitution itself.