It is not just that Donald Trump’s policies on trade are an economically illiterate brand of extreme mercantilism which trample casually over international law and threaten to leave trails of destroyed supply chains in their wake. That would, at least, be predictable. It is also that policy shifts back and forth almost at random, today’s bright idea flatly contradicting last week’s firmly-held conviction.

Soon after pulling out of the nuclear deal with Iran, the US president has signalled a reprieve for ZTE Corp, the Chinese company which had been banned from sourcing vital components from US companies. The ban followed findings that it had illicitly sold products to Iran and North Korea.

The move is not just surprising, given Mr Trump’s hostility towards Chinese manufacturers and their alleged theft of jobs and production from the US. It also directly contradicts the strong views of many top officials in US intelligence and law enforcement, who have repeatedly warned ZTE products could be employed to spy on American users and are a threat to national security.