Trump has used the IEEPA as the legal justification for his tariffs, as the president first levied tariffs on China, Canada and Mexico before issuing and then paring back more sweeping tariffs on most foreign goods, now imposing a baseline 10% on most foreign imports while many Chinese goods face an import fee of at least 145%.

A lawsuit filed Monday challenges the legality of President Trump’s worldwide, across-the-board tariff hikes. The Liberty Justice Center, a libertarian-leaning public-interest law center based in Texas,