The European Union's transformation after Russia's attack on Ukraine

Russia's invasion of Ukraine on 24 February 2022 shattered any remaining illusions that closer economic integration with Europe would lead Russia, over time, towards democracy at home and peaceful coexistence with its neighbors abroad. It reinvigorated the North Atlantic Treaty Organization (NATO) and jolted the European Union (EU) into cutting off trade and energy ties with Russia, while welcoming a massive flow of refugees from war-torn Ukraine. It empowered Central and East European states in the EU, reignited enlargement debates, and shifted NATO and Europe's borders to the north and east. Introducing a special issue, this article argues that the EU's peace through integration strategy has always existed side by side with NATO's peace through strength approach, in a broader European project with blurred boundaries. This war may force the EU to solidify its borders between an internal zone of integration and an external zone of strength projection and geopolitics.