A year has passed since Donald Trump ended an era of relative comity between the two greatest powers in the world. The US president’s trade tariffs against China provoked countermeasures and counter-countermeasures that flustered markets and even inspired some lurid prognostications of a new cold war.

Now, we learn, a truce is in the offing. The two sides are in promising discussions in Washington. An agreement is “closer and closer”, reports Larry Kudlow, the economic adviser to Mr Trump.

Well that, to misquote the internet meme, de-escalated quickly. It is easy to see why. A US-China accord would perk up the economic mood all over the world, and that, for a president 18 months from an election, is an irresistible prize. Mr Trump could offer voters statesmanlike lustre after teasing concessions from a foreign power, without the pain of lasting conflict.