An international nationalist movement sounds like a contradiction. Nationalists are concerned above all by the fortunes of their own tribe. International co-operation does not come naturally to them. And yet, despite this, the world is seeing the emergence of a “nationalist international”. Nationalist political parties are on the rise across the west — and they are taking inspiration from each other and working together.

Donald Trump is central to this development. The US president is often portrayed as an isolated maverick on the world stage. But, in fact, he is emerging as the informal leader of an international movement. By shifting American politics in a more nationalist direction, Mr Trump has changed the tone of politics everywhere.

The US president already has ideological soulmates in Europe, where the key figures include Viktor Orban, the prime minister of Hungary (who came to power before Mr Trump), and Matteo Salvini, Italy’s deputy prime minister. Europe’s nationalists include far-right parties that are now in coalition governments, such as Mr Salvini’s League and Austria’s Freedom Party. But nationalist themes have also been increasingly adopted by more traditional centre-right parties, such as Germany’s CSU, Britain’s Conservatives and Austria’s People’s party.