Minnesota and Canada share so much: frigid winters, a love for hockey — and more recently, massive plumes of toxic wildfire smoke sending people indoors in the peak of summer. It’s that latter experience that’s driving the two neighbors apart and adding to U.S.-Canadian tensions, as Minnesota endures one of its smokiest summers on record from fires burning north of the border. A group of Republican lawmakers from Minnesota is publicly berating the Canadian government, criticizing its handling of hundreds of fires that have polluted their districts, sullying summer tourism and, at times, giving Minnesota some of the worst air in the world. This week, state Rep. Elliott Engen of Lino Lakes, a Republican, filed a complaint asking the U.S. Environmental Protection Agency and the International Joint Commission, a body created to help resolve cross-border disputes, to investigate Canada’s handling of the fires. “Over 20 million residents in the Midwest have faced restrictions on outdoor ...