The signing of the CPTPP trade deal involving 11 countries including Canada and Mexico was only made possible by the signing of side letters. These can complicate the long-term implementation of the deal – for example Canada signed 39 side letters on topics ranging from national culture and intellectual property to automotive tariffs and geographic indications. The deal itself will also complicate Mexico and Canada’s ongoing NAFTA negotiations. While Mexico’s exports to the CPTPP group outside Canada have already increased, by 17% in the past quarter on a year earlier, Canada still ac...