Division and unity: Voter and party perspectives on EU integration under external threat.

The Russian invasion of Ukraine has reshaped European politics, prompting the European Union (EU) to take indirect actions such as aiding Ukraine, accepting refugees, and imposing sanctions on Russia. This special section explores the implications of these events on European unity. Will the war highlight divisions among countries and ideological groups, as "post-functionalists" would predict? Or will the external threat, in line with the "bellicist logic," and EU solidarity, in line with the "polity formation" literature, foster increased EU policy coordination and centralization? The contributions assess the war's impact on the supply (political parties) and demand (public opinion) sides of the politics of European integration. The articles show moderate support for the "bellicist" mechanisms of threat and consensus. They also find solidarity and unity for refugee and energy policy, with greater ideological and country divisions over economic policy, defence policy, and appeasement strategies toward Russia.