Canadian tourists are foregoing travel to the U.S. amid a period of strain in the bilateral relationship, with plummeting visits threatening the American tourism industry and wider American economy. According to data released Monday by Statistics Canada , the number of Canadians making return visits to the U.S. by car fell 4.5 percent in March, when compared to same month last year. It noted that last year’s figures were also impacted by “political tensions between Canada and the United States,”