A gunman killed at least three people at Michigan State University Monday night, injuring five more individuals, who remain in critical condition, before fatally shooting himself.

A motive hasn’t yet been determined in the shooting.

The Michigan State incident is the 68th such mass shooting — an incident during which four or more people are shot, as defined by the Gun Violence Archive — to take place in the US already since the beginning of 2023. It follows mass shootings at two mushroom farms in Half Moon Bay, California, and at a ballroom dance studio in Monterey Park, California.

These shootings come in the wake of numerous others last year including at a Walmart in Chesapeake, Virginia; at an LGBTQ nightclub in Colorado Springs, Colorado; on a school bus allegedly targeting members of the University of Virginia football team; a Fourth of July parade in Highland Park, Illinois; at a hospital in Tulsa, Oklahoma; at an elementary school in Uvalde, Texas; and at a supermarket in Buffalo, New York.

No other high-income country has suffered such a high death toll from gun violence. Every day, 120 Americans die at the end of a gun, including suicides and homicides, an average of 43,475 per year. Since 2009, there has been an annual average of 19 shootings in which at least four people are killed. The US gun homicide rate is as much as 26 times that of other high-income countries; its gun suicide rate is nearly 12 times higher.

Gun control opponents have typically framed the gun violence epidemic in the US as a symptom of a broader mental health crisis. But every country has people with mental health issues and extremists; those problems aren’t unique. What is unique is the US’s expansive view of civilian gun ownership, ingrained in politics, in culture, and in the law since the nation’s founding, and a national political process that has so far proved incapable of changing that norm.

“America is unique in that guns have always been present, there is wide civilian ownership, and the government hasn’t claimed more of a monopoly on them,” said David Yamane, a professor at Wake Forest University who studies American gun culture.

Last year, Congress reached a deal on limited gun reforms for the first time in nearly 30 years. But the recent shootings underscore why narrow reform won’t stop mass shootings — and just how embedded gun violence is in the US.

The US has a lot of guns, and more guns mean more gun deaths

It’s hard to estimate the number of privately owned guns in America since there is no countrywide database where people register whether they own guns, and there is a thriving black market for them in the absence of strong federal gun trafficking laws.

One estimate from the Small Arms Survey, a Swiss-based research project, found that there were approximately 390 million guns in circulation in the US in 2018, or about 120.5 firearms per 100 residents. That number has likely climbed in the years since, given that one in five households purchased a gun during the pandemic. But even without accounting for that increase, US gun ownership is still well above any other country: Yemen, which has the world’s second-highest level of gun ownership, has only 52.8 guns per 100 residents; in Iceland, it’s 31.7.

American guns are concentrated in a tiny minority of households: just 3 percent own about half the nation’s guns, according to a 2016 Harvard and Northeastern University study. They’re called “super owners” who have an average of 17 guns each. Gallup, using a different methodology, found that 42 percent of American households overall owned guns in 2021.

Researchers have found a clear link between gun ownership in the US and gun violence, and some argue that it’s causal. One 2013 Boston University-led study, for instance, found that for each percentage point increase in gun ownership at the household level, the state firearm homicide rate increased by 0.9 percent. And states with weaker gun laws have higher rates of gun-related homicides and suicides, according to a study by the gun control advocacy group Everytown for Gun Safety.

The link between gun deaths and gun ownership is much stronger than the link between violence and mental health issues. If it were possible to cure all schizophrenia, bipolar, and depressive disorders, violent crime in the US would fall by only 4 percent, according to a study from Duke University professor Jeffrey Swanson, who examines policies to reduce gun violence.

There’s still a pervasive idea, pushed by gun manufacturers and gun rights organizations like the National Rifle Association, that further arming America is the answer to preventing gun violence — the “good guy with a gun” theory. But a 2021 study from Hamline University and Metropolitan State University found that the rate of deaths in 133 mass school shootings between 1980 and 2019 was 2.83 times greater in cases where there was an armed guard present.

“The idea that the solution to mass shootings is that we need more guns in the hands of more people in more places so that we’ll be able to protect ourselves — there’s no evidence that that’s true,” Swanson said.

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The prevalence of the self-defense narrative is part of what sets apart the gun rights movement in the US from similar movements in places like Canada and Australia, according to Robert Spitzer, a professor at SUNY Cortland who studies the politics of gun control.

Self-defense has become by far the most prominent reason for gun ownership in the US today, eclipsing hunting, recreation, or owning guns because they’re antiques, heirlooms, or work-related. That’s also reflected in ballooning handgun sales, since the primary purpose of those guns isn’t recreational, but self-defense.

American gun culture “brings together the hunting-sporting tradition with the militia-frontier tradition, but in modern times the hunting element has been eclipsed by a heavily politicized notion that gun carrying is an expression of freedom, individuality, hostility to government, and personal self-protection,” Spitzer said.

That culture of gun ownership in the US has made it all the more difficult to explore serious policy solutions to gun violence after mass shootings. In high-income countries lacking that culture, mass shootings have historically galvanized public support behind gun control measures that would seem extreme by US standards.

Canada banned military-style assault weapons two weeks after a 2020 mass shooting in Nova Scotia. In 2019, less than a month after the Christchurch massacre, New Zealand lawmakers passed a gun buyback scheme, as well as restrictions on AR-15s and other semiautomatic weapons, and they later established a firearms registry. The 1996 Port Arthur massacre in Australia spurred the government to buy back 650,000 firearms within a year, and murders and suicides plummeted as a result.

By contrast, nearly a decade passed after the 2012 school shooting at Sandy Hook Elementary School in Newtown, Connecticut, before Congress passed a new gun control law. The Bipartisan Safer Communities Act, the law passed in June 2022, was relatively limited: it did not ban any types of weapons, instead incentivizing states to enact new measures meant to limit who can access guns.

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“Other countries look at this problem and say, ‘People walking around in the community with handguns is just way too dangerous, so we’re going to broadly limit legal access to that and make exceptions on the margins for people who might have a good reason to have a gun,’” Swanson said. “Here we do just the opposite: We say that, because of the way that the Supreme Court interpreted the Second Amendment, everybody has the right to a gun for personal protection, and then we tried to make exceptions for really dangerous people, but we can’t figure out who they are.”

While the majority of Americans support more gun control restrictions, including universal background checks, a vocal Republican minority unequivocally opposes such laws — and is willing to put pressure on GOP lawmakers to do the same. Alongside the NRA, and a well-funded gun lobby, this contingent of voters sees gun control as a deciding issue, and one that could warrant a primary challenge for a lawmaker who votes for it.

The gun lobby has the advantage of enthusiasm. “​​Despite being outnumbered, Americans who oppose gun control are more likely to contact public officials about it and to base their votes on it,” Barnard College’s Matthew Lacombe explained in 2020. “As a result, many politicians believe that supporting gun regulation is more likely to lose them votes than to gain them votes.”

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Congress in June passed a bipartisan gun safety bill for the first time since the 1990s. But the new law — which incentivized states to pass red flag laws, enhanced background checks for gun buyers under 21, and closed the “boyfriend loophole” which allowed some people with domestic violence convictions to purchase guns — is not sufficient to fully address the causes of mass shootings. Certain studies suggest that even truly universal background checks may have limited effects on gun violence.

The Supreme Court has made it impossible to cure America’s gun violence epidemic

In 2008, the Supreme Court effectively wrote NRA CEO Wayne LaPierre’s “good guy with a gun” theory into the Constitution. The Court’s 5-4 decision in District of Columbia v. Heller (2008) was the first Supreme Court decision in American history to hold that the Second Amendment protects an individual right to possess a firearm. But it also went much further than that.

Heller held that one of the primary purposes of the Second Amendment is to protect the right of individuals — good guys with a gun, in LaPierre’s framework — to use firearms to stop bad guys with guns. As Justice Antonin Scalia wrote in Heller, an “inherent right of self-defense has been central to the Second Amendment right.”

As a matter of textual interpretation, this holding makes no sense. The Second Amendment provides that “a well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.”

We don’t need to guess why the Second Amendment protects a right to firearms because it is right there in the Constitution. The Second Amendment’s purpose is to preserve “a well-regulated Militia,” not to allow individuals to use their weapons for personal self-defense.

For many years, the Supreme Court took the first 13 words of the Second Amendment seriously. As the Court said in United States v. Miller (1939), the “obvious purpose” of the Second Amendment was to “render possible the effectiveness” of militias. And thus the amendment must be “interpreted and applied with that end in view.” Heller abandoned that approach.

Heller also reached another important policy conclusion. Handguns, according to Scalia, are “overwhelmingly chosen” by gun owners who wish to carry a firearm for self-defense. For this reason, he wrote, handguns enjoy a kind of super-legal status. Lawmakers are not allowed to ban what Scalia described as “the most preferred firearm in the nation to ‘keep’ and use for protection of one’s home and family.”

This declaration regarding handguns matters because this easily concealed weapon is responsible for far more deaths than any other weapon in the United States — and it isn’t close. In 2019, for example, a total of 13,927 people were murdered in the US, according to the FBI. Of these murder victims, at least 6,368 — just over 45 percent — were killed by handguns.

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Last year, the Supreme Court made it even harder for federal and state lawmakers to combat gun violence. In its decision in New York State Rifle & Pistol Association v. Bruen, it massively expanded the scope of the Second Amendment, abandons more than a decade of case law governing which gun laws are permitted by the Constitution, and replaces this case law with a new legal framework that, as Justice Stephen Breyer writes in dissent, “imposes a task on the lower courts that judges cannot easily accomplish.”

The immediate impact of Bruen is that handguns — which are responsible for the overwhelming majority of gun murders in the United States — could proliferate on many American streets. That’s because Bruen strikes the types of laws that limit who can legally carry handguns in public, holding that “the Second and Fourteenth Amendments protect an individual’s right to carry a handgun for self-defense outside the home.”

One silver lining for proponents of gun regulation is that the majority opinion, written by Justice Clarence Thomas, embraces language that first appeared in Heller, which permits some gun laws such as prohibitions on “dangerous and unusual weapons.” Nevertheless, it placed an emphasis on historical analogies that could endanger many laws that enjoy broad bipartisan support. The future of firearm regulation looks grim for anyone who believes that the government should help protect us from gun violence.

Update, February 14, 2023, 10 am: This story, originally published on May 26, 2022, has been updated with details from the February 13 Michigan State University shooting.