“Don’t do stupid shit.” With the last word turned demurely into “stuff”, this became known as the “Obama doctrine”. It reflected the lessons Barack Obama had learnt from his presidential predecessor’s unnecessary Iraq war. For many, the doctrine was defeatist. Today, I see its merits. It would be wonderful to see intelligent action in response to our many challenges. Yet, today, application of the Obama doctrine would be a relief.

This is true, not least, for the world economy. As Kristalina Georgieva, the new managing director of the IMF, said in her curtain raiser for this week’s annual meetings in Washington DC: “In 2019, we expect slower growth in nearly 90 per cent of the world. The global economy is now in a synchronised slowdown.” Joint research by the Brookings Institution and Financial Times is bleaker still, describing our situation as “synchronised stagnation”.

What is driving this slowdown, particularly stark in industry and trade? A big part of the answer seems to be rising uncertainty. This, argue the Brookings authors, is due to the “persistent trade tensions, political instability, geopolitical risks, and concerns about the limited efficacy of monetary stimulus”. Such uncertainty has, notes Gavyn Davies , become “entrenched”.