Investors cheered Monday’s announcement of a trade deal with Mexico, and appropriately so. A final agreement is not yet in hand, but if maintained, it could alleviate a portion of the significant trade-related uncertainty investors have been dealing with for more than a year. The agreement would offer a few notable adjustments to the original 1994 North American Free Trade Agreement (NAFTA), which primarily dealt with the trade in goods. The world has changed dramatically since 1994, however, and the value-add of manufacturing skills has been diluted by a proliferation of production capabilities around the world. A nation’s economic worth,...