David Westin: This is a story about déjà vu all over again. This week, the White House announced yet another round of tariffs on Canadian goods, this time charging 50% on imports of a range of items, including milk, hockey equipment, beer, and plywood, but specifically excluding energy and potash, a critical fertilizer used by American farmers. Our special contributor, Chrystia Freeland, served as Canada's finance minister and deputy prime minister.So, Chrystia, we have an announcement now that the Trump ad ...