The negotiations to end the US-Iran war, resulting in the signing of a memorandum of understanding on June 17, have been something of an acid test of Donald Trump’s approach to diplomacy. What does it tell us? And has this US president changed the way diplomacy is done?

When Trump was inaugurated for his second presidency in January 2025, he announced his intention to be both a peacemaker and to pursue an “America first” foreign policy, focused on avoiding wars and bringing direct benefits to the US. By November 2025, he declared he had already settled eight “raging conflicts” across the world.

In January this year, the forced removal of Nicolas Maduro as president of Venezuela and installation of Delcy Rodríguez as a more US-friendly successor led Trump’s deputy chief of staff, Stephen Miller, to tell CNN: “You can talk all you want about international niceties and everything else. But we live in a world, the real world … that is governed by strength, that is governed by force, that is governed by power.”

But the Iran war has shown Trumpian diplomacy colliding with a real world that does not always bend to his will or succumb to US displays of force. The real world, it seems, is more complex than he thought.

Hitherto, five elements have characterised Trump’s approach to diplomacy. First, he prefers to eschew the traditional institutions and mechanisms of diplomacy. The State Department languishes, the UN is ignored. Traditional alliances, multilateral organisations and international gatherings have been disdained, unless they provide a platform for Trump to demonstrate his power and “call the shots”.

Rather than use US ambassadors or diplomats to tackle international issues, Trump relies on a small cast of........

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