A new treaty could stabilize Canada's relationship with the U.S.

Open this photo in gallery: A Canada-United States Economic and Defence Treaty would provide Canada with more certainty during and after the Trump presidency.SUZANNE PLUNKETT/AFP/Getty Images Thomas d'Aquino is the founding CEO of the Business Council of Canada and author of Private Power Public Purpose – Adventures in Business, Politics and the Arts. Prime Minister Mark Carney has rightfully and boldly laid out a vision for Canada to achieve greater economic and security resilience in the face of an "existential threat" from the United States. This demands a posture of greater independence from our southern colossus. It also requires a…