Interstate Trade War Georgetown University Professor Marc L. Busch notes that the trade agreement between Canada and the U.S. forced Canada to liberalize trade between its own provinces. The rules and regulations at provincial level intended to protect local businesses had a trade burden equivalent to a 6.9 percent tariff. The EU’s single market concept still has a lot of work to do as nationalists increasingly resort to protections like country-of-origin labeling, but the U.S. is not innocent in this regard. The Interstate Commerce Clause has been shredded by states like California enacting their own pollution laws and restrictions on how animals and products are produced out of state. The “buy local” emphasis in recent...