European Commission President Ursula von der Leyen has proposed making Canada the first "associate member" of the European Union. But associate membership does not exist. Still, no matter how vague, von der Leyen’s offer was a win for Canadian Prime Minister Mark Carney at a time when he is locked in a trade war with U.S. President Donald Trump. It also offers the EU a firm partnership with another Western democracy as its own ties with and trust in its old ally the United States fade. Now the two sides must define what “associate membership” is.