After a G7 meeting at which his behaviour was eccentric even by his own high standards, Donald Trump has added new and complex layers to the question of how on earth the other big trading powers should deal with him. This is one of the few areas in which experience does not necessarily bring wisdom. The US president’s actions are now so volatile that each extra piece of data, if anything, makes it harder rather than easier to discern his decision criteria and create a game plan accordingly.
Anyone who thought he was playing a cunning game about boosting votes in the heartlands, for example, has to explain why he is doubling down on tariffs against China despite increasing cries of pain from American farmers hit by retaliation.
So, with a nascent US-Japan trade deal emerging, deadlines ahead for the EU and tensions escalating with China, how do those involved plan on dealing with Mr Trump?