The United Kingdom is not a nation-state but a political union. It was formed by the coming together, over centuries, of territories which retained their own national identities and institutions. Key questions of demos (the people), telos (the purpose of union), ethos (binding values) and the locus of sovereignty were never definitively resolved. Since 1999, Scotland, Wales and Northern Ireland have had their own self-governing institutions within the Union. Devolution was an effort to stabilize the Union in the face of centrifugal pressures, but it left the same key questions unresolved. The Union is now contested in all four of its component parts and fundamental questions are raised about the meaning of political, social and economic union. Unionism, as doctrine and practice appears to have lost its way, unable to adjust to devolution. Brexit has added to the strains because membership of the European Union provided an external support system for the union of the United Kingdom itself. Yet the UK cannot easily fall apart into its constituent nations, and public opinion still appears largely content with the idea of a plurinational union. There is no definitive answer to the question of state and nation within the United Kingdom.