Both liberal and conservative justices appeared skeptical that the claims could clear hurdles in U.S. law that largely shield gun makers from lawsuits when their products are used in crime.
Big-name manufacturers like Smith & Wesson appealed to the justices after a lower court let the suit go forward under an exception for situations where gun companies are accused of violating the law.
An attorney for Mexico argued the case over economic harm linked to gun violence is was still in its early stages and should be allowed go forward.
Justice Brett Kavanaugh, though, pointed to arguments that many products can be misused, and a flood of lawsuits could hurt the U.S. economy. “That's a real concern, I think, for me, about accepting your theory,” he said.
Justice Samuel Alito raised questions about whether the U.S. could file suit against Mexico for “illegal conduct” it links to activities there.
Mexico has strict gun laws and has just one store where people can legally buy firearms. But thousands of guns are smuggled in by the country's powerful drug cartels every year.
The Mexican government says 70% of those weapons come from the United States. The lawsuit claims that companies knew weapons were being sold to traffickers who smuggled them into Mexico and decided to cash in on that market.
The companies reject Mexico's claims, arguing the country comes nowhere close to showing they're responsible for a relatively few people using their products to commit violence.
