"We no longer want to do any kind of business with Spain. I would like that to stop. Spain is a terrible partner in NATO. They do not take part, they do not pay. I do not want anything to do with Spain. Cut off all trade with Spain, please, including visits," Donald Trump once again declared at a joint press conference after the NATO meeting in Ankara, with an impassive Mark Rutte looking on.

As a former Dutch prime minister, the secretary general of the Atlantic Alliance could have reminded the US president that responsibility for the EU member states’ trade policy lies with the Commission, albeit with certain nuances.

Since the creation of the single market in 1993, decisions on tariffs, trade agreements and other measures have been an exclusive EU competence. Coercive action against one of the 27 would have direct effects on the rest and would, in all likelihood, trigger a joint response.

Trade flows between two of these countries are not even classed as exports, but as "intra-Community supplies". This interconnection also means, for instance, that oranges grown in Valencia may be processed in another European country before being shipped to the US, making any unilateral action extremely complicated.