The first time White House officials told reporters that the president intended to rip up Nafta, in the spring of 2017, I was about to attend the Mexican air show, one of the most important commercial events involving Mexico and the United States.

Billions of dollars in trade between the two countries are at stake during the show, where a host of American aerospace suppliers demonstrate their wares. As the ambassador to Mexico, I would have expected to have been told what the president intended to do about the most vital part of our relationship with Mexico.

But this is not how things work in the Trump era.

I learned about the draft one-page notification of our plan to exit Nafta from countless emails and phone calls from reporters and Mexican officials. Now I was going to spend a hot April afternoon with the Mexican president, Enrique Peña Nieto, without warning or instructions from Washington. What was I supposed to tell him?