On Wednesday, gun rights is back at the Supreme Court for the first time in over a decade. The justices will be weighing the constitutionality of a New York law that imposes limits on carrying guns outside the home, setting up a showdown over just how far the Second Amendment goes.

Depending on what the justices do, this case could have a much bigger impact on Americans’ lives — and the fate of gun regulations more broadly — than the court’s last blockbuster gun rights decision. Although that decision, released in 2008 as part of a case called District of Columbia v. Heller, profoundly shifted the law around the Second Amendment by determining that the amendment covered the personal right to own a gun, it directly affected only a handful of gun restrictions. And research conducted over the past 10 years hasn’t found a big shift in how lower courts are interpreting the Second Amendment; few gun laws have been struck down as a result.

That could change this time. At a minimum, striking down the New York law would likely result in changes to concealed-carry regulations in at least six other states, which could mean more guns on the streets of the nation’s two biggest cities. And if the court’s conservative majority decides to issue a more sweeping decision, this case could also open the door for a flood of challenges to other gun restrictions.

The last big gun rights ruling left lots of restrictions in place

The Supreme Court’s ruling in Heller was undeniably a big deal, at least symbolically. For more than 200 years, the federal courts had approached the Second Amendment as a right that belonged to a “well-regulated militia” as outlined in the Constitution — not an individual person’s right to own a gun. But colonial-era militias faded away relatively quickly, which made it pretty much impossible for anyone to successfully argue that their Second Amendment rights were being violated, according to Darrell Miller, a professor at Duke University School of Law.

That changed after 2008. In the Heller ruling, a five-justice Supreme Court majority said that focusing on the militia was a misunderstanding of the core meaning of the Second Amendment. Americans did possess an individual right to carry guns in defense of their home, much as gun rights advocacy groups like the National Rifle Association had been arguing for the past few decades. In his dissent, Supreme Court Justice John Paul Stevens called it a “law-changing decision” and a “dramatic upheaval in the law.”

Stevens was right — and wrong. Heller was a fundamental change in constitutional rights. “It was a big deal to have the Supreme Court of the United States say to gun rights advocates, ‘Yes, actually, you have a meritorious argument about a Second Amendment right to have a gun in the home,’” Miller said.

But on a practical level, Heller’s impact was quite limited. In the majority opinion, Supreme Court Justice Antonin Scalia stressed that there were still plenty of circumstances in which gun regulations were constitutional. “Nothing in our opinion,” he wrote, “should be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms.”

And over the next 10 years, the decision didn’t revolutionize gun laws. In a study, law professors Eric Ruben and Joseph Blocher analyzed over 1,000 lower-court decisions involving the Second Amendment between June 26, 2008 — when Heller was decided — and February 1, 2016. They found that very few of those cases were successful. In many cases, judges quoted Scalia’s caveat in their opinion, underscoring the fact that they saw plenty of room for regulation within the Heller decision.

“Many people feared or hoped that gun laws would fall like dominoes [after Heller],” Ruben said. But that hasn’t proved to be the case. In fact, Ruben added, “judges of all ideological stripes have been upholding gun laws.”

But this gun rights case could change regulations across the country

The case the justices will hear this term, though, directly addresses one of the most important questions left open by Heller: Can states put restrictions on Americans’ ability to carry guns in public for self-defense? 

Specifically, they’ll be weighing a New York law that requires applicants for gun licenses to show “proper cause,” generally understood to mean a heightened need for self-defense in the public sphere. At least six other states, including California, have similar laws, which means that striking down the New York regulation would have far-reaching implications. Those states would likely need to modify their restrictions in ways that would allow a lot more people to obtain guns. And that would have an impact on a lot of people, since it’s currently extremely difficult to get a concealed-carry permit in large cities like New York and Los Angeles.

Gun rights advocates argue that looser regulations on concealed weapons would actually make those cities safer, since everyday people would be in a better position to defend themselves. But there’s a lot of evidence suggesting that’s not true. Multiple studies have suggested that a heavily armed populace doesn’t increase safety — in fact, one study found that relaxing permit requirements was associated with an increase in violent crime.

It’s not just the fate of concealed-carry restrictions that could hang in the balance in this case, though. The Supreme Court could issue a far-reaching ruling that not only strikes down New York’s law but also sets out a whole new way of evaluating whether gun regulations are constitutional — calling many kinds of gun laws into question.

There are clues to how the court could do this in a sequel case to Heller that was decided by the U.S. Court of Appeals for the District of Columbia in 2011, when now-Justice Brett Kavanaugh was a circuit court judge on the panel. Kavanaugh dissented from the majority opinion, which upheld a D.C. ban on semiautomatic weapons. He argued that when considering the constitutionality of gun regulations, judges should use an approach that weighs the “text, history, and tradition” of a given kind of law. 

Some of the other conservatives could be open to that line of thinking. Justice Amy Coney Barrett, a self-proclaimed textualist, was skeptical of gun restrictions as a lower-court judge, too, going so far as to argue in a 2019 dissent that some felons shouldn’t be stripped of their rights to own guns. Justice Clarence Thomas has also been outspoken about his desire to take on more gun cases. In 2018, he dissented from the Supreme Court’s decision not to hear a case about a California gun law, calling the Second Amendment a “constitutional orphan.”  And the third Trump appointee, Justice Neil Gorsuch, has less of a paper trail on gun rights, but advocates expect him to be sympathetic to textualist arguments — much as Scalia was.

It’s hard, of course, to predict how the justices will come down in this specific case, and even Kavanaugh’s approach wouldn’t necessarily spell the end of gun regulation, since as Ruben pointed out, gun regulation has existed for a long time in the United States — in fact, the New York law that’s being challenged is more than 100 years old. But it could lead to a lot of complications, since guns are much deadlier now than when the Second Amendment was written, and the mass violence that gun regulations are designed to combat is itself a modern phenomenon, which could make a historical approach pretty challenging.

But as Ruben pointed out, this approach could leave plenty of room for discretion on the part of judges trying to figure out whether gun laws are constitutional, which is important because the federal judiciary is much more conservative than it was 10 years ago. “Trying to decide whether a modern taser law is sufficiently similar to historical laws on muskets or other weapons — there’s so much subjectivity in that,” he said. More broadly, Americans’ gun rights are also still being worked out in real time. “It’s being articulated and developed for the first time in our lifetimes, and that makes it unique among constitutional rights,” Ruben said. 

That means there’s a lot of room for the new conservative majority to shape gun rights in America going forward — if they can get on the same page about what that should look like.