This publication analyzes how the European Union can best react to the current threats and challenges Europe faces. Some of these threats include: the geopolitical threats at the external borders, such as the Russia/Ukraine crisis; the on-going conflicts in the Middle East; the anti-democratic tendencies in Turkey; and the unrest in Northern Africa. Other challenges include migration, combat of terrorism, climate change, and-since Donald Trump took office-the EU's relationship with the United States. The EU's internal problems are related to the economic crisis, the impact migration has on national societies, populism, and the withdrawal of the United Kingdom from the EU (Brexit). Common action to counter these threats and challenges is needed. However, EU cooperation is essentially a voluntary process, whereas the problems referred to concern politically highly sensitive issues. Moreover, new steps in the integration process require consensus between all the Member States. In view of the increasing number of Member States and the heterogeneity which has gradually arisen between them, such a requirement is difficult to attain. Therefore, concrete proposals for more flexible and differentiated cooperation are presented. They vary from models of enhanced cooperation, the establishment of an EU Security Council, to simplification of the ordinary treaty amendment procedure. [Subject: International Law, EU Law]