Mexico’s attempt to place America’s largest gun businesses on the hook for cartel violence concerns found a cold reception before the Supreme Court this week.

On Tuesday, The Court heard oral arguments in Smith & Wesson v. Mexico, a case pitting a foreign government against the American gun industry with up to $10 billion at stake. The entire dispute centers around the 2005 Protection of Lawful Commerce in Arms Act (PLCAA), which generally prohibits lawsuits against gun businesses for harms perpetrated by third parties using their legal products. Though the law has long been a political flashpoint, the Supreme Court has not weighed in on the bounds of its protections or exceptions until now.

While the justices questions revealed a high level skepticism for Mexico’s specific claims against Smith & Wesson, they didn’t necessarily paint a clear picture of how far they think gunmaker liability extends.

The PLCAA’s predicate exception allows for lawsuits against the gun industry for actions that “knowingly violated a State or Federal statute applicable to the sale or marketing of the product.” But it also requires that “the violation was a proximate cause of the harm for which relief is sought.”

Mexico’s theory for fitting its suit into that exception involves claiming that gun manufacturers aid and abet violations of federal law. Mexico argues the companies knowingly provide their firearms to dealers who sell them to gun traffickers, often through straw purchasers, and that those traffickers later arm cartel members who commit violent acts with them on the other side of the southern border.

Right off the bat, that theory of aiding and abetting liability creating an opening through the PLCAA was greeted with skepticism. Justice Clarence Thomas opened the justices’ discussion by questioning whether Mexico had identified a violation of any specific state or federal statute on the part of the gun companies in its complaint.

“The exception is for knowingly violating a state or federal statute, and it would seem helpful in determining aiding and abetting and then eventually proximate cause if that comes up if you knew which statute we were dealing with,” he said.

The lack of specificity in Mexico’s allegations was a theme that appeared several times throughout the oral argument, as justices from across the ideological spectrum repeatedly probed Mexico’s claims. When it became clear that Mexico was claiming that certain gun dealers selling to illegal straw purchasers was the violation in question—even though it is only suing manufacturers and a wholesaler in this case—three separate justices questioned why it couldn’t even identify the supposed law-breaking retailers.

“But what you don’t have is particular dealers, right?” Justice Elena Kagan asked Mexico’s attorney, Catherine Stetson. “I mean, there are lots of dealers. And you’re just saying they know that some of them [sell to straw purchasers]. But which some of them? I mean, who are they aiding and abetting in this complaint?”

“Are there any allegations in the complaint that the Petitioners knowingly sell to specific red flag dealers?” Justice Samuel Alito asked.

“You haven’t sued any of the retailers that were the most proximate cause of the harm,” Justice Amy Coney Barrett said. “And you haven’t identified them that I can tell in the complaint.”

Other justices appeared to read Mexico’s aiding and abetting claims as a thinly veiled attempt to advance the same liability suit that the PLCAA precludes.

“How is your suit different from the types of suits that prompted the passage of PLCAA?” Justice Thomas asked.

Similarly, Justice Ketanji Brown Jackson repeatedly invoked her concern that Mexico’s suit struck at the very heart of the PLCAA.

“My point is that Congress didn’t want general aiding and abetting concerns to be what is imposing duties on these manufacturers,” Jackson said. “I mean, if you look at your lawsuit and what you’re asking for, you’re asking for changes to the firearm industry, safety practices, the distribution practices, the marketing, all of the things that you ask for in this lawsuit would amount to different kinds of regulatory constraints that I’m thinking Congress didn’t want the courts to be the ones to impose.”

Finally, practical concerns surrounding the impacts it would have for The Court to accept Mexico’s theory of aiding and abetting liability worried Justice Brett Kavanaugh.

“What do you do with the suggestion on the other side and in the amicus briefs that your theory of aiding and abetting liability would have destructive effects on the American economy in the sense that, as you’ve read in the briefs, lots of sellers and manufacturers of ordinary products know that they’re going to be misused by some subset of people?” Kavanaugh asked, citing car and pharmaceutical manufacturers as examples. “That’s a real concern for me about accepting your theory of aiding and abetting liability.”

However, while a healthy dose of suspicion toward Mexico’s aiding and abetting claims was a constant theme of the argument, at least a handful of justices indicated they want a fairly narrow ruling, particularly on the issue of proximate cause. Noel Francisco, the lawyer arguing on behalf of the gun companies, faced some of his toughest questions from the justices on how to identify a gun company as the proximate cause of harm with a firearm.

“As to proximate cause, this Court has repeatedly said there must be a direct relationship between the defendant’s conduct and the plaintiff’s injury,” he said in his opening remarks. “But no such relationship exists if plaintiff’s injury is caused by multiple intervening independent crimes committed by foreign criminals on foreign soil to inflict harm on a foreign sovereign.”

Conservative and liberal justices alike probed this proximate cause analysis. They seemed to want to avoid drawing too narrow a line on the issue, particularly in cases involving foreseeable harm.

“Put aside aiding and abetting,” Justice Neil Gorsuch asked. “Assume for the moment that your clients aided and abetted the sale of guns to bad apple dealers, ones they knew or intended even for them to sell on to people in Mexico doing bad things. They knew that. They knew all of that. How would you not have proximate cause in that hypothetical?”

“I still don’t think that establishes proximate cause when you have an intervening independent crime,” Francisco responded.

“Counsel, the complaint says that 2 percent of the guns manufactured in the United States find their way into Mexico, and I know you dispute that, but is there a number where your legal analysis might have to be altered?” Chief Justice John Roberts asked. “If it’s 10 percent, if it’s 20 percent? At some point, the proximate cause lines that you draw really can’t bear the weight of the ultimate result.”

In the end, however, some justices signaled they may be content to decide the case without resolving the question of proximate cause at all.

“Is there any reason for us to reach the proximate cause question if we conclude for aiding and abetting that you win?” Barrett asked.

“I think for us to go into proximate cause opens up a Pandora’s box,” Sotomayor added.

Overall, the justices’ comments suggested a win for the gun manufacturers, but perhaps one cabined to Mexico’s specific claims. That would be a significant loss for gun-control advocates hoping for a way around the gun industry’s liability protections, but not a lasting defeat.

If SCOTUS declines to outline what constitutes proximate cause in tort suits against gun businesses for third-party crimes, gun-control activists will likely continue filing their own PLCAA workarounds over alleged violations of “public nuisance” and similar state-level statutes. Those have become increasingly popular in recent years.

So, even if the Supreme Court squashes Mexico’s PLCAA suit, there’s a good chance it won’t be the last.