The U.S. Commerce Department’s section 232 reviews of steel and aluminum came just before the seventh round of NAFTA negotiations, and risk damaging relations with Mexico as well as Canada. While Mexican exports of the products under review were only 6% of U.S. imports, they were worth $2.8 billion in 2017. The U.S. took 70% of Mexican exports of those products, making it likely the Mexican government will aggressively push for exemptions. Key products exported include flat-rolled uncoated ($638 million of exports in 2017) and coated steels ($508 million) as well as steel pipes used f...