In her State of the Union speech, Ursula von der Leyen offered Canada the status of the EU's first "associate member". Mark Carney, the Canadian prime minister, was sitting in the hall. The idea sounded big: a new alliance for the future, built on top of the existing trade agreement between Brussels and Ottawa.

Donald Trump responded by threatening to cut off trade entirely. Speaking to reporters at the airport in Charlotte, he said the proposal was ridiculous, that Canada is a terrible trading partner, and that if he reads this as a hostile act towards the US he will impose very high tariffs or halt trade with Europe altogether across several sectors. He left a small door open - if the intentions are good, there is room to negotiate.

The problem is that nobody knows what "associate membership" means

This is where the story gets interesting. No such status exists in EU law. The proposal took European capitals themselves by surprise - nobody clarified what obligations it carries, what rights it confers, or through which procedure it is obtained. Von der Leyen threw the idea out from the podium, and Brussels has been trying to find a definition for it ever since.

Even Canada is backing away from its own offer. The incoming Canadian ambassador to the EU, Jonathan Wilkinson, quickly cooled expectations - we are not at that stage, we are working on concrete results. Carney is due to address MEPs, but the enthusiasm from that hall evidently did not survive a single day.

What this looks like from over here

Macedonia has been queuing for the EU for more than twenty years. Albania and Montenegro are opening chapters one at a time. And then, in the course of one evening, a new category of membership is invented for a country on the other side of the Atlantic - with no definition, no procedure, no criteria. No chapters, no benchmarks, no expert mission arriving to check whether everything is by the rules.

Candidate states in the Balkans have spent years being told the process is technical, that it is merit-based, and that no shortcut exists. This week Brussels demonstrated that a shortcut does exist - it just depends who is asking. Will anyone explain to people in Skopje, Tirana and Podgorica why a rulebook gets written for them while for others a speech is enough?

The tariffs are the real message

What Trump did is not a comment about Canada. It is a reminder addressed to Brussels that EU foreign policy carries a price in dollars. Europe wants to show it can build alliances without Washington - and Washington answers with the one argument that always works: trade.

If the European Union cannot offer even associate membership to a friendly state without drawing a tariff threat, that says something about the real weight of its independent policy. For now the proposal is a sentence from one speech. The threat, on the other hand, comes from a man who has already shown twice that tariffs are not an empty word for him.