In all its atrocity, the Russian invasion of Ukraine may serve to recall that the democratisation of Europe is both a momentous achievement and an ongoing challenge. The democratisation of Europe, which started in the middle of the 20th century in reaction to the atrocities of the Second World War, can be described as the historic undertaking to change a belligerous continent into a democratic union of democratic states. The achievements of the European quest for ‘ever closer union’ are so original that politicians and scholars still have to coin the terms with which to name them. A democratic union of democratic states is a new concept in international relations, which is based on the equally innovative practice of shared exercise of sovereignty. From the perspective of the UN-system of global governance, the European Union constitutes an unprecedented phenomenon too. The Charter of the United Nations, which was adopted in the aftermath of the Second World War, distinguishes between states and unions of states. As the EU in its present form does not fit the description of either category, its existence also requires the introduction of a new term in the field of international relations. Considering that the distinctive hallmark of the EU in relation to other international and regional organisations consists of its democratic character, the EU may be identified for the purposes of international affairs as a democratic international organisation.