WASHINGTON — Unifor president Jerry Dias says he and U.S. Secretary of Commerce Wilbur Ross have agreed that combating low Mexican wages is the key to breaking the impasse at NAFTA renegotiations. Both agreed that Canada and the United States have been hurt by the siphoning off of manufacturing jobs to Mexico and must work together to pressure the country to drive up wages, Dias said Tuesday in Washington, D.C. …Unifor said other key issues addressed at the meeting between Dias and Ross included the imposition of duties on Canadian softwood lumber exports to the U.S. Dias said they were unable to find common ground on softwood lumber and doesn’t anticipate a resolution to the dispute any time soon.