The author is an FT contributing editor and writes the Chartbook newsletter

Remember January 2021? Joe Biden came into office loudly proclaiming: “America is back!” Antony Blinken, as secretary of state, was fond of remarking that “l(fā)ike it or not, the world does not organise itself”. The claim to US leadership extended across the board: to trade and defence, tech and climate. Given its huge per capita emissions, the idea that the US could really be a leader on decarbonisation stretched credulity. But the new mood in Washington was welcome.

Now, less than four years later, the Republicans rule the roost. On defence and trade policy there will be continuities from Biden to Donald Trump. But on climate, the US is once more halfway out the door.