AMNA NAWAZ: Mexican officials argued today at the U.S. Supreme Court that American gunmakers should be held libel for cartel violence in their country.

GEOFF BENNETT: Mexico is seeking billions of dollars from several major U.S. firearm manufacturers and one gun wholesaler in an effort to be reimbursed for costs related to gun violence.

Stephanie Sy has more.

STEPHANIE SY: The Mexican government estimates that 200,000 firearms are smuggled into the country from the United States each year, and the vast majority of guns found at Mexican crime scenes come from the U.S. Mexico argues that American gun manufacturers are aiding illegal sales to Mexican criminals, and it claims cartel violence is directly connected to those sales.

A 2005 law generally shields firearms manufacturers and others along the supply chain from civil liability, but Mexico is trying to argue for an exception.

Joining me now to discuss the suit and today's Supreme Court hearing is Chip Brownlee.

He's a reporter with The Trace, a nonprofit news organization that covers gun violence.

Chip, I'm sure you listened to the arguments this morning.

Even the typically liberal justices did not seem convinced by the Mexican government's arguments against Smith & Wesson.

And "News Hour"'s Supreme Court analyst, Marcia Coyle, told me that the majority of justices seemed skeptical that there was a direct connection between the gun manufacturers and the injury Mexico claimed.

Why did they seem to face such an uphill battle?

CHIP BROWNLEE, The Trace: So one part about the Protection of Lawful Commerce in Arms Act is that it requires, for there to be an exception for someone to sue a defendant in the gun industry, they have to prove that the defendant violated a state or federal law, and that their violation of the law was the proximate or a close cause to a harm that has been alleged.

And I think what happened here is essentially that Mexico laid out this pretty broad case that hundreds of thousands of guns are smuggled from the U.S. to Mexico every year, but that the actual link between the gun manufacturers and the guns on the ground in Mexico that wind up in the hands of cartels, that link wasn't exactly clear.

So I totally agree.

I think, listening to it, you saw most, if not all of the judges seeming skeptical of Mexico's argument.

And I think we could see even a unanimous verdict in this case.

STEPHANIE SY: What is Mexico accusing the gun manufacturers of doing that would amount to aiding and abetting and make the case an exception to that 2005 law?

CHIP BROWNLEE: So Mexico is essentially alleging here that the gun manufacturers and distributors are marketing their guns to the cartels.

So one example that came up in the case is this Colt handgun that was marketed as El Jefe, which, like, almost -- which literally means boss, but is a term that refers to a cartel boss.

Some other things that they alleged was that the gun manufacturers are refusing to make changes to their weapons, like making it harder to deface a serial number, which is -- serial numbers are very important when you're tracing a gun, and also just kind of the general marketing of these weapons as military-style or military-grade weapons, which would make them better or seem better to the cartel.

STEPHANIE SY: If the justices don't decide in favor of Mexico, Chip -- and we do expect a decision by the end of the term in June -- if the gun companies don't address their concerns, if U.S. courts are hamstrung by the 2005 law, what other options are there to stop these guns from getting into the hands of violent criminals?

CHIP BROWNLEE: If the Supreme Court rules against Mexico, and that could essentially make it much more difficult for these types of civil lawsuits to be brought against the gun industry, and that would result in a situation where, if you're actually going to try to stop any of this trafficking, you're going to have to do it through a law enforcement means.

So that would require the ATF, Border Patrol, the other federal law enforcement agencies to actually do more to stop this.

But I also don't think we have really seen any kind of significant funding put towards that.

I mean, the ATF's funding and their personnel have been cut in years past.

So I think the only other option really is that law enforcement angle, but the resources aren't there.

STEPHANIE SY: And yet we hear nonstop about drug trafficking and human trafficking at the southern border.

Those are top priorities for U.S. politicians.

Does that discussion need to include how American policies and American companies are arming the cartels?

And does gun smuggling have a direct impact on crime in the U.S.?

CHIP BROWNLEE: Absolutely.

That's part of the argument that Mexico is making here, that somewhere between 250,000 and 500,000 guns flow illegally across the border,and those are the guns that the cartels and other violent groups in Mexico are using to perpetrate their violence.

And I think the argument there is that, if you were able to cut off that supply, then you could potentially end up in a situation where there's less fentanyl trafficking, there's less human trafficking coming across the border, and you could mitigate maybe some of that violence that's really the root cause of migration in general.

So I think Mexico is making this argument that it could be good for the U.S. if they were to win this case.

STEPHANIE SY: That is Chip Brownlee, a reporter with The Trace.

Chip, thank you so much.

CHIP BROWNLEE: Thank you.