(AP Photo/Marco Ugarte) O n August 31, the administration sent a formal notification to Congress that starts the countdown to a vote on an agreement that could replace the 1994 North American Free Trade Agreement (NAFTA). After a 90-day waiting period required by the “fast-track” procedure , an agreement could be signed on November 30, not coincidentally the last day in office for the current Mexican president. This would set up a U.S. congressional vote in the first half of 2019. Much of the media coverage since the notice has focused on the legal and political uncertainties related to the fact that, so far, the United States has only concluded a deal with Mexico. Indeed, the formal notice indicated “intent to sign a trade agreement with Mexico—and Canada, if it is willing—90 days from now.” Negotiations with Canada continue this very day, Wednesday, in Washington, D.C. Canada rejoined talks last week after disengaging in May over opposition to U.S. demands that a new deal include a...