America’s regulations on gun purchases don’t make much sense no matter how you feel about the Second Amendment. By federal law, only people 21 and older can buy a handgun from a licensed dealer, but 18-year-olds can buy shotguns and rifles—including the infamous AR-15.

In 2012, the National Rifle Association implored the U.S. Supreme Court to fix this inconsistency—by allowing people under 21 to buy handguns. In its petition, the gun-rights group told the justices that young Americans should not be deprived of their constitutional right to buy a specific class of firearms. “It is undisputed that 18-to-20-year-olds were not only permitted but required to keep and bear arms when the Second Amendment was ratified,” the NRA’s lawyers wrote. A group of conservative attorneys general from 22 states filed a brief backing the NRA’s petition.

For whatever reason, in what has become a trend on gun cases, the court decided not to accept the challenge.

Five years later, after a 19-year-old gunman killed 17 people with an assault rifle at Marjory Stoneman Douglas High School in Parkland, Florida, something may have finally changed in America’s stagnant debate over the Second Amendment. Media-savvy survivors of the school shooting, raised on active-shooter drills, have become unusually effective advocates of gun control. Florida Governor Rick Scott, a Republican and longtime ally of the NRA, has backed a number of reforms the group surely opposes. Even President Donald Trump, who campaigned as avowed supporter of “Second Amendment people,” may support new restrictions.

In this fight, gun-control advocates have a powerful silent ally: the U.S. Supreme Court. It’s been almost a decade since the justices agreed to hear a case on the Second Amendment, despite multiple opportunities to do so. Without review by the high court, state courts and lower federal courts effectively have free reign to determine the scope of the “right of the people to keep and bear arms.” Many of those courts have signed off on some of the toughest restrictions on the books in recent years, clearing a path for gun-control activists to take advantage of the post-Parkland moment.

This isn’t how the legal battle over gun restrictions was supposed to go. Gun-rights activists won a massive victory in 2008’s D.C. v. Heller, when the court struck down the District of Columbia’s handgun ban and strict rifles and shotgun regulations. The ruling marked the first time that the court held that the Second Amendment protects an individual right to bear arms. Because of D.C.’s unique status as a federal district rather than a state, the ruling only applied to the U.S. government until McDonald v. Chicago two years later, when the court’s conservative majority applied it to the states, too.

Both sides of those rulings seemed to anticipate legal mayhem after the rulings. “The decision will encourage legal challenges to gun regulation throughout the nation,” Justice Stephen Breyer wrote in his Heller dissent, adding that “litigation over the course of many years, or the mere specter of such litigation, threatens to leave cities without effective protection against gun violence and accidents during that time.” Perhaps in a nod to those concerns, Scalia wrote a passage in his opinion for the Heller majority that explicitly said the ruling shouldn’t call into doubt most existing gun regulations.

Like most rights, the right secured by the Second Amendment is not unlimited. From Blackstone through the 19th-century cases, commentators and courts routinely explained that the right was not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose.... Although we do not undertake an exhaustive historical analysis today of the full scope of the Second Amendment, nothing in our opinion 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.

Since this sea change, however, the Supreme Court hasn’t taken up another major Second Amendment case. It hasn’t been for a lack of opportunities, either: The court has eschewed cases on issues ranging from trigger locks to age restrictions for purchases. In 2015, the justices turned down a challenge to a Chicago suburb’s assault-weapons ban. (The court never weighed in on the federal assault-weapons ban, which lapsed in 2004.) In 2017, they also declined to review California’s stringent thresholds on applications for a concealed-weapons license. All of the restrictions at hand had been approved by lower courts.

In its 2012 petition on handgun purchases for young adults, the NRA deplored the judiciary’s refusal to broaden the Second Amendment’s scope. “Instead, jurisdictions have engaged in massive resistance to the clear import of those landmark decisions,” the organization warned the justices, “and the lower federal courts, long out of the habit of taking the Second Amendment seriously, have largely facilitated the resistance.”

The trend continues. Earlier this month, the court had a chance to take up a challenge to California’s latest waiting-period law, which imposes a ten-day window—the second-longest in the country—on any gun purchase in the state. Gun-rights advocates argued that the Ninth Circuit Court of Appeals gave California too much leeway in crafting the restriction, but the high court declined to hear Silvester v. Becerra. That drew a stern rebuke from Justice Clarence Thomas, who has staked out one of the most expansive visions of the Second Amendment on the court’s current bench. “The right to keep and bear arms is apparently this Court’s constitutional orphan,” he complained in his dissent of the court’s decision. “And the lower courts seem to have gotten the message.” The Supreme Court’s “continued refusal to hear Second Amendment cases,” he added, “only enables this kind of defiance.”

It’s not clear why the Supreme Court has suddenly gone gun shy. Not reviewing a lower court’s decision isn’t the same as agreeing with it, of course. The court only takes up a small portion of the thousands of civil and criminal cases that it’s asked to consider each year. Drawing broad conclusions from the justices’ refusal to hear any single case would be foolhardy in normal circumstances. But the court’s aggregate silence on gun cases after Heller and McDonald stands out.

New gun-control measures will still face opposition in all but the bluest of states. But with the high court quiescent and the lower courts lenient, whatever proposed restrictions in state legislatures and Congress that make it into law would likely survive judicial scrutiny. State lawmakers in Maine, Tennessee, and Washington are pushing for bans on bump stocks, which increase a semi-automatic rifle’s rate of fire. Montana, Pennsylvania, and Georgia are considering a range of tighter mental-health restrictions for background checks of gun buyers.

Even more forceful restrictions may pass the courts’ muster. One of the starkest revelations since the Parkland shooting is how many warnings local police and the FBI received about the alleged gunman in advance. One potential legislative fix would give family members and cops more tools to prevent a troubled gun owner from resorting to violence. Five states have “red flag laws,” which allow law enforcement agencies to seize a person’s firearms if they believe he or she is an imminent danger to themselves or others. Legislators in 20 other states are mulling similar bills, and Democrats introduced one at the federal level in May.

In Florida, where the Parkland shooting has upended the state’s approach to gun control, the state legislature is mulling a bevy of new restrictions. Governor Scott is calling for raising the minimum age to buy a rifle or shotgun from 18 to 21. And Florida Attorney General Pam Bondi, who five years ago urged the Supreme Court to loosen gun purchasing restrictions for 18-to-20-year-olds, told Trump last week that the state is going to create a “Gun Violence Restraining Order,” allowing authorities to confiscate guns from someone who has been civilly committed.

There’s no telling when the Supreme Court will finally take another Second Amendment case. But if these proposals in Florida and elsewhere become law, the evidence suggests they have a good chance of withstanding whatever challenges the NRA might bring. That’s all the more reason for the gun control movement to sustain its momentum in the wake of Parkland.