By James McCarten THE CANADIAN PRESS WASHINGTON- Canada is “extremely concerned” about the potential fate of the Line 5 pipeline, emissaries warned Tuesday in advance of a Wisconsin court hearing that threatens to shut down what they call a vital cross-border oil and gas corridor. The warning from Canada’s embassy in Washington, D.C., comprised Ottawa’s first formal comments about the pipeline in months, a lengthy, measured statement that nonetheless made plain its fears for Line 5’s future. And it leaned hard into three areas always sure to get attention in the U.S.: protecting American jobs and growth, defending continental energy security and honouring treaty obligations to an important and trusted ally. “The energy security of both Canada and the United States would be directly impacted by a Line 5 closure,”…