A lawsuit filed at the Court of International Trade targets the heart of President Trump’s trade agenda, the Section 232 steel and aluminum tariffs. An industry group that represents steel importers and traders will also challenge the constitutionality of the law that gave the president the power to enact the tariffs. The American Institute for International Steel filed the lawsuit, along with two of its member companies, and seeks a court order preventing further enforcement of the 25 percent tariff increase. The tariffs are impacting multiple U.S. industries, from equipment manufacturers, brewing companies that use aluminum cans, automakers and nail and fastener makers. The tariffs, according to the industry group, has prompted a 50 percent increase in product prices for U.S. steel-using manufactures. Additional waves of impacts are expected through retaliatory tariffs, including those from China on U.S. agricultural products that are set to start late next week.