April 5, 2019—Canadian Foreign Minister Chrystia Freeland on Thursday cautioned against the idea of reopening a new continental trade pact with the United States and Mexico, saying it could be a “Pandora’s box."

One part of the deal - which was signed last November after 15 months of sometimes rancorous negotiations - was a chapter designed to boost labor standards and wages in Mexico, reported Reuters.

Freeland reiterated that Canada could find it hard to press ahead with efforts to ratify the treaty as long as U.S. maintained tariffs on imports of Canadians steel and aluminum.