As President Donald Trump pressures Mexico to address the flow of migrants and drugs heading north into the United States, the Supreme Court is set to hear arguments Tuesday in a major appeal about one thing that’s crossing the border toward Mexico: guns.

U.S. firearms maker Smith & Wesson and distributor Interstate Arms have appealed a lower court's ruling that the lawsuit could proceed on the grounds that Mexico has plausibly alleged that the companies aided and abetted illegal gun sales,