The US Supreme Court is about to decide its first Second Amendment case in more than a decade. Its decision could severely limit the options available to state lawmakers that are considering gun control measures in the wake of a recent streak of major mass shootings.

The case, New York State Rifle & Pistol Association Inc. v. Bruen, concerns a more than 100-year-old New York law that requires anyone who wants a license to carry a concealed handgun in public to show “proper cause,” or a specific need to defend themselves.

The court’s conservative majority seemed to favor striking down that “proper cause” provision during oral arguments. But how it goes about doing so has important implications for states that want strong gun control laws.

If the ruling is more limited, the Court could remove a critical barrier that has restricted the number of people who can legally carry a concealed handgun in New York and seven other states with similar laws. The Supreme Court might rule more broadly, however, and use the case as a vehicle to create a new standard by which courts must evaluate all Second Amendment cases. Essentially, that would reopen the debate over a whole set of legal questions around gun control policy that were previously considered settled.

Should the justices do that, states potentially would not only need to rethink concealed weapon laws but also a slew of other gun control ones — from minimum age restrictions to assault weapons bans.

The court could just rule narrowly on the New York law

If the New York “proper cause” provision is struck down, it would become far easier to legally carry a concealed handgun in the state. And it would come at a moment when New York City is grappling with a 16 percent increase in shootings over the last year.

A court decision would also potentially undermine similar laws in California, Massachusetts, New Jersey, Maryland, Rhode Island, Delaware, and Hawaii, though those states would likely try to differentiate their laws from the New York one and argue that they should be upheld. Together, those eight states are home to about 80 million people, or about one-quarter of the US population, and they each have lower-than-average gun violence rates.

The court could also rule more broadly

If the justices go even further in creating a new legal framework to evaluate Second Amendment cases, the decision could also reignite legal fights over a swath of other gun control measures, embroiling states in court battles over laws that have been on the books for years.

Right now, courts typically take into account a number of factors when evaluating Second Amendment cases challenging gun regulations. That includes how guns have been regulated historically, social science research, and whether the regulation impacts the core Second Amendment right to have a firearm in your home for self-defense.

Second Amendment advocates, however, have argued that the courts should look exclusively to the history and tradition of permissible regulation at the time that the Second Amendment was adopted in 1791. The Supreme Court could adopt that framework through Bruen.

Rewriting how courts evaluate gun control policies in that way would put “a burden on jurists to understand history at a particular point in time and declare a right, even though they’re here in modern day and are not historians,” said Esther Sanchez-Gomez, senior litigation attorney with Giffords Law Center to Prevent Gun Violence. It could also result in inconsistent rulings if different jurists interpret history differently.

Such a ruling would also effectively undermine previous gun control rulings made under the current legal framework, Sanchez-Gomez said, which would lead to the “re-litigation of all of the laws that have already been upheld under the Second Amendment.”

That would have ripple effects that “extend well beyond” the New York law at issue in the case, potentially throwing states’ age limitations, assault weapon bans, large capacity magazine restrictions, taser restrictions, and other policies onto shaky legal footing, said Eric Ruben, a Brennan Center for Justice fellow and assistant professor of Law at SMU Dedman School of Law.

“Every weapon law you can imagine would have to be considered under this new methodology,” he said. “That could unsettle all of those issues that we thought were more or less resolved in lower courts.”

Gun control advocates are already gearing up for those potential legal attacks from pro-gun states and organizations.

“We’re ready to stand by states and cities who are looking to pass gun safety laws and help them defend those laws,” said Janet Carter, director of issues and appeals at Everytown Law.

States are readying their other options to restrict gun access

New York Gov. Kathy Hochul, who recently pushed through a gun control package in the wake of last month’s mass shooting at a supermarket in Buffalo, has already announced that she will consider calling a special session of the state legislature if the Supreme Court strikes down the state law.

One thing that lawmakers might consider is explicitly defining and expanding the kinds of “sensitive locations” where concealed guns cannot be carried. The Supreme Court explicitly did not rule out restrictions on guns in sensitive locations and even named schools and government buildings as examples in its 2008 decision in District of Columbia v. Heller, the last major Second Amendment case it took up. If states like New York can’t keep people from carrying concealed guns through its “proper cause” licensing requirement, then they might be able to do so in a broader array of public spaces.

“I think that we could expect some effort both at the state and at the local level, to be more specific about where it’s not permissible to carry guns. How broadly policymakers go will determine how likely it is that it’s going to get litigated,” Ruben said.

Essentially, states would be more limited when it comes to restricting concealed carry than they are now, but they would still be able to take some steps to keep concealed guns from being allowed everywhere. They still have means to restrict the number of guns that are on the streets, but they’ll have to look for workarounds if they can’t require that gun owners show “proper cause” to concealed carry.