And then there was one. With the exception of Jim Mattis, the US defence secretary, Donald Trump has now cleared the decks of people who stand up to him. The ousting of Rex Tillerson, whose firing was announced on Twitter, eliminates the gap between Mr Trump’s anti-globalist instincts and the stance of America’s chief diplomat. Mike Pompeo, Mr Tillerson’s replacement, shares the president’s undiplomatic mindset. Mr Pompeo is a Trump enabler. Mr Trump’s America First foreign policy is now closer to becoming a reality.

The portents for the world are far-reaching. One of Mr Tillerson’s greatest sins was to call Mr Trump a “moron”. His leaked outburst followed a meeting in which the president had said that the US should multiply its nuclear weapons arsenal tenfold. Mr Tillerson’s derogatory response broke two cardinal rules of working for Mr Trump. The first was to show disloyalty, which Mr Trump cannot abide. Questioning his IQ is taboo. The second was to repeatedly clash with him on the big questions. In practice they amount to the same thing.

Gary Cohn, who resigned last week as Mr Trump’s economic adviser, also broke both rules. Last summer he told the Financial Times that he disapproved of Mr Trump’s even-handedness on the alt-right’s clash with protesters in Charlottesville. He also argued against Mr Trump’s protectionist instincts — as did Mr Tillerson. HR McMaster, Mr Trump’s national security adviser, is no longer seen as a brake on Mr Trump — and his days are widely rumoured to be numbered.