Trade negotiations used to be underpinned by an unspoken assumption: that trade barriers were lose-lose propositions. All sides could gain something if they mutually disarmed. …[They] were always about how much tariffs and other walls would go down, not how much they would go up. …United States Trade Representative Jamieson Greer sums up the Trump administration’s break with the postwar trade consensus, saying the administration is “focused on reshoring supply chains related to automotive, steel, aluminum … If Canada wants to come in and participate in this type of reshoring we’re trying to do, we’re happy to have those discussions.” …The U.S. wants higher tariffs at home, and lower tariffs abroad. The old give-and-take is now take-and-take. …”We want to have production here. We don’t necessarily want to be dependent on China, Canada or anybody else for things like cars.” [This article is only available to subscribers to the Globe and Mail]