The U.S. Supreme Court declines to hear thousands of cases each year, so in one sense, Monday’s announcement that it wouldn’t take up Friedman v. Highland Park wasn’t much of a surprise. But among the 130 cases the Court declined to grant certiorari on Monday morning, only one elicited a dissent from two justices.

Arie Friedman challenged Highland Park’s assault-weapons ban, which prohibits residents from buying, selling, or owning some types of semiautomatic firearms. The Seventh Circuit Court of Appeals upheld the Chicago surburb’s ban by narrowly interpreting the Court’s recent Second Amendment rulings, which focused on handguns.

That ruling, Justice Clarence Thomas wrote in his dissent from the denial of certiorari, “eviscerated many of the protections recognized” by the Supreme Court. More importantly, he argued, the Court’s refusal to summarily reverse the Seventh Circuit or even hear the case at all risked “relegating the Second Amendment to a second-class right.” Justice Scalia joined his opinion without comment.

Monday’s refusal to hear Friedman is the latest episode in the Supreme Court’s strange silence on the Second Amendment since handing down two landmark rulings, D.C. v. Heller and McDonald v. Chicago, in 2008 and 2010. As the national debate over the role of firearms in American society intensifies with each mass shooting or proposed gun-control measure, the justices have refused to hear a single major gun-rights case since they applied the Second Amendment to the states five years ago.

The Court’s silence hasn’t been for want of a significant case. In June, the justices declined to hear a challenge to San Francisco’s requirement that handguns must be either disabled with trigger locks or stored in locked containers when not in use. The city ordinance was similar, though not identical, to the one struck down by the Supreme Court in D.C. v. Heller in 2008. Last year, the justices ignored two NRA-led cases challenging federal and state age restrictions on firearm purchases. And in 2013, the Court refused a case that sought to overturn New York’s strict regulations on carrying handguns outside the home.

The cumulative effect of these denials (and many others) is a bizarre unwillingness to participate in a legal revolution that the Court itself ignited. First, some history. For most of the republic’s existence, the Bill of Rights, including the Second Amendment, only applied to the federal government. Then, in the 1927 case Gitlow v. New York, the justices ruled that the Fourteenth Amendment’s Due Process Clause extended the protections of the First Amendment’s Free Speech Clause to laws passed by state and local governments. The ruling sparked a slow-burning revolution in American constitutional law over the next half-century as the justices steadily began what constitutional scholars refer to as “selective incorporation”: the application of the Bill of Rights to the states, piece by piece.

State constitutions already protected many rights in many states, but some of the Court’s incorporation rulings still led to seismic changes, especially in criminal law. In Mapp v. Ohio in 1961, the Court incorporated the exclusionary rule, a Fourth Amendment remedy that prevents the use of illegally obtained evidence during trials, to the states, where most criminal trials in the U.S. take place. Two years later, in Gideon v. Wainwright, the Court also incorporated the Sixth Amendment’s assistance-of-counsel clause and ruled that the states had to provide a lawyer for criminal defendants who could not afford one in felony cases, leading to the creation of the modern public-defender system.

By the late 1960s, the Court had expanded most of the Bill of Rights to the states. But the Second Amendment remained an outlier. Only a smattering of cases had addressed it since the Civil War, and those that did often weren’t favorable to the gun-rights movement: U.S. v. Cruikshank, a Reconstruction-era case, explicitly stated that the Second Amendment didn’t apply to the states, and the 1939 case U.S. v. Miller upheld the restrictions of the federal National Firearms Act.

As Michael Waldman noted in his recent history of the Second Amendment, virtually all judges and constitutional scholars believed until recently that there was no constitutional right to individual gun ownership. Chief Justice Warren Burger, a staunchly conservative Nixon appointee, called the idea “a fraud on the American public” in a 1980 interview. The most notable gun-related case of the Rehnquist Court, U.S. v. Lopez, struck down the Gun-Free School Zones Act of 1990 for exceeding Congress’s power to regulate interstate commerce, not for violating the Second Amendment.

Then, in two successive rulings in 2008 and 2010, the Supreme Court dramatically reversed course. First, in a 5-4 decision in Heller, the Court ruled that, lo and behold, the Second Amendment did protect an individual’s right to bear arms. Scalia, writing for the majority, relied heavily on English legal history and colonial-era texts to outline the Founders’ intent to protect that right. At the same time, he dismissed those who noted that despite this historical record, the Court itself had never before found such a right. “Other provisions of the Bill of Rights have similarly remained unilluminated for lengthy periods,” he argued. “For most of our history the question did not present itself.”

Heller was a triumph of the gun-rights movement, which spent decades dragging the idea out of the hinterlands of American constitutional thought and into the Supreme Court’s rulings. But despite the fears of some and the hopes of others, the decision was more restrained than it could have been. D.C.’s handgun law was among the strictest in the country, making it an easy target for legal activists but limiting its factual relevance for future challenges to other city and state gun laws. In his opinion for the Court, Scalia also indicated that Heller should not throw most of the nation’s gun laws into chaos.

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. For example, the majority of the 19th-century courts to consider the question held that prohibitions on carrying concealed weapons were lawful under the Second Amendment or state analogues. 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.

More importantly, the decision only applied to D.C. itself and to the federal government; it would take another ruling to apply it to the states. Two years later, the same 5-4 majority of justices incorporated the Second Amendment to strike down Chicago’s handgun ban in McDonald. Citing the historical record, Justice Samuel Alito wrote that “it is clear that the Framers and ratifiers of the Fourteenth Amendment counted the right to keep and bear arms among those fundamental rights necessary to our system of ordered liberty.”

Throughout their opinions in McDonald, both sides braced for future legal challenges to gun laws nationwide. Justice John Paul Stevens complained that the Court “unleashed in Heller a tsunami of legal uncertainty,” citing hundreds of Second Amendment challenges filed in the lower courts in the previous two years. Alito countered those fears with the Court’s past reassurances.

We made it clear in Heller that our holding did not cast doubt on such longstanding regulatory measures as “prohibitions on the possession of firearms by felons and the mentally ill,” “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.” We repeat those assurances here. Despite municipal respondents’ doomsday proclamations, incorporation does not imperil every law regulating firearms.  

Five justices formed the majorities in Heller and McDonald: Scalia, Thomas, Alito, Justice Anthony Kennedy, and Chief Justice John Roberts. All of them remain on the Court today. The Court does not identify how justices vote when granting or denying certiorari petitions, but four votes are required to grant a case. We can therefore logically conclude that at least two justices from the Heller/McDonald majority have refused to take a single Second Amendment case in the last five years.

That does not mean that the same two justices voted against hearings in every single case—Alito and Thomas could have voted against some, for example, while Scalia and Kennedy might have voted against others. More than two justices could have also voted against hearings in some cases. In Friedman, for example, Roberts might have voted to hear the case but chosen not to disclose his vote or join Thomas's dissent. And it’s also possible that the entire Heller/McDonald majority is voting to block further Second Amendment cases with the help of one or more dissenters, though that seems unlikely given how many of the denied cases undercut Heller and/or McDonald.

If the justices had accepted one or two firearm-related cases or their silence was limited to a single term or two, it would be irresponsible to speculate. But a five-year silence on the Second Amendment amid a number of major cases suggests something deeper is at work. Maybe it’s the high-profile mass shootings since McDonald. Or the rise in shootings in Chicago since they struck down the city’s handgun ban. Or maybe they’re waiting for more consensus to emerge among the federal circuit courts before revisiting the questions. Or maybe they’re just waiting for the right one.