The gun makers reject those claims. They appealed to the Supreme Court to overturn a ruling that let the lawsuit move forward even though U.S. law largely shields gun makers from lawsuits.
Depending on how the court rules, it could also affect a narrow legal path that helped families of the mass shooting at Sandy Hook Elementary School secure a $73 million settlement from the gun maker Remington.
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.
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 gun makers say there is no evidence the industry allows trafficking and they disagree with Mexico's data about how many weapons originate in the U.S. The Mexican government, not U.S. gun makers, is responsible for enforcing the laws and fighting crime, they argue.
The industry is shielded from most civil lawsuits arising from crimes committed using firearms under a 20-year-old law, though Mexico has argued that it doesn't apply to crimes committed outside of the U.S.
The gun companies are asking the justices to overturn an appeals court ruling that allowed the case to move forward.
