The state is back. The post-1945 multilateral order is falling into disrepair. Everywhere you look, nationalism is on the march. States, established and rising, are disinterring traditional notions of national sovereignty. They want to reclaim the international system created by the Peace of Westphalia in 1648. They are chasing a chimera.

For a moment, after the collapse of communism, the future belonged to a postmodern state. This state would remain the essential building block of political organisation, but would recognise shared interests. Governments would discard narrow concepts of national interest in favour of co-operative security and prosperity. Strange though it seems to say after the tumult of recent years, but the EU was seen as a model for the new international order.

There was more to this than utopian daydreaming. Globalisation has tightened the ties of economic interdependence. Threats to nations are recognisably international in character – from climate change to pandemics, from terrorism and the proliferation of unconventional weapons to mass migration. Mobile capital, cross-border supply chains and the connections of the digital age leach power from individual states. The way to recapture lost authority is to act in concert.