The Supreme Court on Tuesday appeared likely to block a historic $10 billion lawsuit against U.S. gun makers as both conservative and liberal justices raised concerns about allowing the government of Mexico to hold firearm manufacturers liable for cartel violence south of the border.

Federal law grants broad immunity to the gun industry, in part to protect companies from costly litigation that could drive them out of business. Mexico alleges the law creates an exception for “aiding and abetting” the illicit sale and trafficking of guns, which the companies deny.

Mexico has only one gun store but is awash in millions of American-made weapons, most funneled into the country by straw purchasers in the United States. The country claims the companies, including Smith & Wesson, Glock, Beretta and Colt, knowingly distribute and market their guns to be trafficked.

By one estimate, at least 200,000 guns flow south of the border each year. The country is seeking $10 billion in damages and court-mandated safety requirements around the marketing and distribution of guns.

“The laws broken here are designed to keep guns out of criminals’ hands. Those violations put guns in criminals’ hands and those criminals harmed Mexico,” Cate Stetson, Mexico’s attorney, told the Supreme Court.

“These acts were foreseeable,” she added. “This court need not vouch for Mexico’s allegations, but it must assume they are true. … Mexico should be given a chance to prove its case.”

Many of the justices seemed unconvinced by Mexico’s case should be allowed to move forward.

Justice Sonia Sotomayor suggested the alleged harms from cartel violence roiling Mexico are too far removed from the manufacturers’ decisions to distribute their products.

“We have repeatedly said mere knowledge is not enough [for liability],” Sotomayor said. “You have to aid and abet in some way. You have to intend and take affirmative action to … participate in what they’re doing.”

Justice Elena Kagan questioned what she perceived as a lack of specificity in Mexico’s allegations.

“There are lots of [gun] dealers. And you’re just saying [the gunmakers] know that some of them [engage in trafficking]. But which some of them? I mean, who are they aiding and abetting in this complaint?” Kagan said.

After Stetson alleged deliberate marketing of guns to cartels, Chief Justice John Roberts voiced skepticism of the claim.

“I mean, there are some people who want the experience of shooting a particular type of gun because they find it more enjoyable than using a BB gun,” he said. “And I just wonder exactly what the defendant, the manufacturer, is supposed to do in that situation. You say no, he shouldn’t be marketing a particular legal firearm because they’re going to go into Mexico at a higher percentage than others?”

Justice Brett Kavanaugh raised concern about the broader implications of a decision allowing Mexico’s suit to go forward.

“What do you do with the suggestion on the other side … that your theory of aiding and abetting liability would have destructive effects on the American economy in the sense that … lots of sellers and manufacturers of ordinary products know that they’re going to be misused by some subset of people?” he asked. “They know that to a certainty, that it’s going to be pharmaceuticals, cars, what — you can name lots of products. So that’s a real concern, I think.”

Stetson replied, “If you have a product manufacturer of a dangerous product that is alleged to have done all of the things knowing who they’re selling to and what is being done with that product, then and only then, I think, that product manufacturer … has a problem.”

More than 160,000 people in Mexico were killed by guns between 2015 and 2022, according to an analysis by Everytown for Gun Safety.

A large majority of guns involved in the shootings came from U.S. border states. More than 40% of illegal guns seized in Mexico over a five-year period came from Texas, according to a U.S. Government Accountability Office report.

In 2023 alone, more than 2,600 firearms were seized going south into Mexico, up 65% from the year before, according to the Department of Homeland Security, and 115,000 rounds of ammunition were captured headed the same direction, up 19% from 2022.

A federal district court dismissed Mexico’s case in 2022 citing immunity under federal law. The 1st U.S. Circuit Court of Appeals reversed that decision in early 2024, saying Mexico had made a plausible case for liability under the law’s exception.

The Supreme Court is expected to decide by the end of June whether or not a liability case can move forward.