Fed by a steady stream of mass shootings and rising public anger about Congress’s inaction, the gun control movement has gained new life. All of the Democratic presidential contenders have put gun policy reform near the top of their platforms, and some lawmakers are considering proposals for buybacks and licensing once thought impossible. Yet the Supreme Court appears ready to douse that momentum — in a case the justices, according to their rules, should not even be hearing at all.

On Monday, the court will hear a challenge to a now-repealed New York City regulation that limited where New Yorkers could bring their guns. It is the court’s first major Second Amendment case in nearly a decade. With two new justices appointed by President Trump, the court could now make it much harder for lawmakers to stem the tide of gun violence and keep guns off their streets.

The case arises just as gun control advocates were beginning to make headway on reform. Although people often complain that nothing changed after the 2012 mass shooting in Newtown, Conn., in truth, the gun debate has been transformed since then by the emergence of a strong, well-financed and politically active movement for gun reform. New advocacy groups such as Mike Bloomberg’s Everytown for Gun Safety and Gabrielle Giffords’s super PAC are putting unprecedented resources into electing pro-reform candidates and ballot measures, in some races even outspending the National Rifle Association. March for Our Lives, organized by students from Parkland, Fla., and Moms Demand Action have inspired the grass roots to get more involved than at any time in the past 30 years.

This political energy has led numerous states, including California, Colorado, Washington and New York, to try to close the loopholes that Congress won’t fix, including universal background checks and bans on military-style rifles and high-capacity magazines. About 1 in 2 Americans live in states that have enacted significant new gun laws since 2012 — far from nothing.

The fact that all of the contenders for the Democratic presidential nomination are backing broad new gun laws also marks a sea change. In the 2008 and 2012 elections, Barack Obama shied away from talking about gun reform, emphasizing instead the right to keep and bear arms. Before Newtown, the prevailing wisdom in Democratic circles was that proposing gun restrictions would hurt you on Election Day. Today, every Democratic candidate is betting otherwise. And for good reason: A Washington Post poll found gun policy was a top issue for voters in Virginia, where Democrats just won control of both houses of the state legislature for the first time since 1994.

Meanwhile, the National Rifle Association is suffering from a massive internal upheaval that has resulted in the ouster of its board president, head lobbyist, longtime lawyers and the public relations firm responsible for the organization’s messaging for three decades. Chief executive Wayne LaPierre has survived but faces the continuing pressure of attorney general investigations by New York and Washington, D.C., of the organization’s compliance with nonprofit law.

The NRA doesn’t have to be all that strong, however, if the Supreme Court begins to read the Second Amendment expansively to outlaw more and more forms of gun control. That is what gun control advocates fear from the case to be heard Monday.

It is possible that the justices could rule narrowly. New York City’s regulation, which severely restricted where lawful gun owners could transport their firearms, was unique; no other city or state has such draconian restrictions. The court could say that New York simply went too far, writing an opinion with no real effect on other cases.

Yet several of the justices have made it clear that they would like to see a much broader and more consequential ruling. Justice Clarence Thomas has complained that the lower courts have been too willing to uphold gun restrictions, accusing the courts of treating the Second Amendment as a “second-class right.” Justice Neil M. Gorsuch has also called for the Supreme Court to strengthen Second Amendment protections.

These justices apparently want to adopt a stricter test for courts to apply in Second Amendment cases, making it harder for gun laws to survive a legal challenge. If the court follows suit in the New York case, recent reforms such as red flag laws and universal background checks could be imperiled.

Or the court might use the case to articulate broad new principles on possessing guns in public. To date, the court has ruled only that the Second Amendment protects your right to have a gun in your home. If the justices hold that citizens have a right to transport or carry guns in public, that could undermine the laws in major cities like New York, Los Angeles and Boston that prohibit most residents from carrying concealed weapons. Today, Los Angeles has only a few hundred civilians with concealed carry permits; tomorrow, it could be a few hundred thousand.

The shocking thing about such a transformation of these American cities is that it would come from a case that is moot — meaning there is no longer any real legal controversy. Fearing a near-certain loss in the Supreme Court, New York City repealed the challenged provisions this year, and the New York state legislature enacted a law prohibiting such restrictions from being adopted in the future. Those challenging the New York City gun rules say lawmakers could one day adopt another law limiting Second Amendment rights. But anyone could say that about any hypothetical law imaginable.

More than two centuries ago, the Supreme Court turned down a request by President George Washington and announced it would not issue advisory opinions on proposed or hypothetical legislation. To ensure the best arguments are made, the court insists on real, live controversies involving actual laws capable of being enforced presently. New York City’s repealed gun restrictions, by contrast, have been wiped from the books and can’t ever be enforced against anyone.

The court should adhere to its long-standing bar on advisory opinions and refuse to rule on these dead and buried gun laws. For gun control advocates, that result would be a welcome respite, but hardly a long-lasting one. Even if the court drops the New York case, there are several other cases challenging gun laws waiting to be heard by the justices. It may only be a matter of time before the court, under the banner of the Second Amendment, makes it even harder for any cities or states to enact meaningful gun laws.

Felicia Sanders is grappling with an unexpected casualty of the deadly Emanuel AME shooting — the loss of connection to the church that shaped her life. (The Washington Post)

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