Heller? Toddlers? Death? What the debate’s gun discussion was all about.

Last night, a lot of Americans tuning in to the final presidential debate between Donald Trump and Hillary Clinton probably ended up with a question: Who the hell is Heller?

The name came up in the course of the debate’s section about the Supreme Court and the Second Amendment. Specifically, the name was a reference to a 2008 decision by the Court, District of Columbia v. Heller, that effectively expanded and validated Americans’ right to privately own a firearm for self-defense.

Trump didn’t seem to have much of a clue what Heller was, and all of his statements about it were vague — typically repeating the hints moderator Chris Wallace dropped about the ruling. (#TrumpBookReport.)

Clinton, meanwhile, described Heller in strong, frightening terms: “What the District of Columbia was trying to do was to protect toddlers from guns. So they wanted people with guns to safely store them. And the Court didn’t accept that reasonable regulation. But they’ve accepted many others. So I see no conflict between saving people’s lives and defending the Second Amendment.”

Some conservatives focused on the “toddler” part of the statement, pointing out that the Supreme Court decision dealt with a DC special police officer’s right to own a gun, not toddlers. As Andrea Noble wrote for the Washington Times, “...the word ‘toddler’ doesn’t appear in the landmark case, which is more widely known for striking down the District’s near-total ban on handgun ownership and for establishing for the first time that the Second Amendment does guarantee a right to keep a gun in the home for self-defense.”

It is true that the decision is more widely known for striking down DC’s handgun ban. But it did also have something to do with gun storage and safety — measures that do have something to do with toddlers, even if the Supreme Court didn’t explicitly say it. And, really, with just about any gun measure, some toddlers are going to be involved — America not only has extraordinary levels of gun violence for a developed country, but as part of this problem it also has a lot of cases of kids tragically shooting themselves in accidents.

So what exactly was the DC law in question, and what did the Supreme Court do about it? Here’s what you need to know.

What the Supreme Court decided in District of Columbia v. Heller

Alex Wong/Getty Images

The DC law had two big parts. First, it effectively banned handguns — by making it illegal to carry an unregistered firearm while banning residents from registering handguns (although the police chief could issue one-year licenses). Second, it required lawful firearm owners to keep their guns unloaded and disassembled or bound by a trigger lock or a similar device, with exceptions for firearms in a place of business or sport.

Dick Anthony Heller, from whom the case gets its name, was a special police officer in DC at the time. He argued that the law violated his Second Amendment rights to own a firearm, particularly for self-defense. For one, he wanted to own a handgun, and the DC police chief denied his license application. But he also went further, arguing that having to keep his gun unloaded, disassembled, or trigger-locked while in his house made him unable to defend himself if, say, an intruder broke in.

Supporters of DC’s law argued that the Second Amendment doesn’t guarantee the right to own a firearm for self-defense. They said the Second Amendment refers only to a person’s right to own a firearm while in “a well regulated militia” and, therefore, people need to be part of a militia to have a right to bear arms. As the Second Amendment says, “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.”

The Supreme Court sided with Heller. In a majority opinion written by Justice Antonin Scalia, the Court declared that the Second Amendment does defend a person’s right to own a gun for self-defense. The legal website Oyez summarized Scalia’s rationale:

To read the Amendment as limiting the right to bear arms only to those in a governed military force would be to create exactly the type of state-sponsored force against which the Amendment was meant to protect people. Because the text of the Amendment should be read in the manner that gives greatest effect to the plain meaning it would have had at the time it was written, the operative clause should be read to “guarantee an individual right to possess and carry weapons in case of confrontation.”

So Scalia concluded that the Second Amendment does not require membership in “a well regulated militia” and the Constitution allows Heller to keep a loaded handgun at his home.

Justice John Paul Stevens gave one of the dissents to the Court’s decision. Later, in the Washington Post, Stevens argued that Scalia’s ruling in Heller and a separate ruling in McDonald v. Chicago, which effectively applied the ruling in Heller to Chicago and other local and state governments, overturned centuries of legal understanding about the Second Amendment:

For more than 200 years following the adoption of that amendment, federal judges uniformly understood that the right protected by that text was limited in two ways: First, it applied only to keeping and bearing arms for military purposes, and second, while it limited the power of the federal government, it did not impose any limit whatsoever on the power of states or local governments to regulate the ownership or use of firearms. Thus, in United States v. Miller, decided in 1939, the court unanimously held that Congress could prohibit the possession of a sawed-off shotgun because that sort of weapon had no reasonable relation to the preservation or efficiency of a "well regulated Militia."

When I joined the court in 1975, that holding was generally understood as limiting the scope of the Second Amendment to uses of arms that were related to military activities. During the years when Warren Burger was chief justice, from 1969 to 1986, no judge or justice expressed any doubt about the limited coverage of the amendment, and I cannot recall any judge suggesting that the amendment might place any limit on state authority to do anything.

Nonetheless, Heller and McDonald went into effect. Their immediate impact was that some of DC, Chicago, and other cities’ restrictions on guns — in particular, handgun bans — were struck down.

But the broader effect was what some justices and legal scholars now view as a radical reinterpretation of the Second Amendment. Before, the amendment was read to allow nearly any regulation on privately owned firearms, within some reasonable limits. Now the right to private gun ownership is more broadly shielded by the Constitution.

So Clinton wants to appoint justices who would pull back the decision to allow stricter gun control measures. Trump, insofar as he actually knows what Heller and McDonald are, doesn’t.

Why Clinton brought up toddlers shooting themselves

Pool via Getty Images

So what does any of this have to do with toddlers?

Clinton was specifically referring to the gun storage requirements, which required that lawful gun owners essentially keep their guns disabled at their homes. This is a part of DC’s law that didn’t get as much attention as the District’s handgun ban, but it was also struck down in part because it was too strict and didn’t have an exception for self-defense.

So when Clinton brought up toddlers, her concern appeared to be that children would no longer be protected by safe storage laws and would be more easily able to pick up a parent’s gun and hurt themselves or others. This is particularly true for a handgun that a child can grab and fire more easily than, say, a shotgun or assault rifle.

This was taking aim at a serious public health problem: Previous studies have found that 110 children die in accidental shootings each year in the US.

As Riley Snyder reported for PolitiFact, there is evidence that children’s deaths are some of the deaths the DC law meant to prevent. In a petition appealing a lower court’s decision to the Supreme Court, the DC government argued, “The smaller the weapon, the more likely a child can use it, and children as young as three years old are strong enough to fire today’s handguns.”

Scalia was, however, clear that the Court’s ruling should not be read to declare “the invalidity of laws regulating the storage of firearms to prevent accidents.” As long as there are reasonable accommodations for people who want to own a firearm for self-defense, and therefore want to keep a loaded gun in their home readily available, safe storage laws should be constitutionally allowed.

As a result, several courts have concluded since Heller that local and state lawmakers can impose some safe storage requirements on firearms — as long as they don’t ban handguns entirely or prevent someone from carrying a loaded gun in his or her home.

America’s gun violence problem reaches much further than toddlers

DC’s law, however, had to do with much more than toddlers. It was trying to tackle an issue that is far bigger, tragically, than 110 accidental shooting deaths each year: The US has far, far more gun violence than other developed countries, in large part due to the country’s lax gun laws.

Javier Zarracina/Vox

The US has nearly six times the gun homicide rate of Canada, more than seven times Sweden’s, and nearly 16 times Germany’s, according to United Nations data compiled by the Guardian. (These gun deaths are a big reason America has a much higher overall homicide rate, which includes non-gun deaths, than other developed nations.)

And there appears to be a correlation between America’s high levels of gun violence and gun ownership, as this chart from Tewksbury Lab shows:

Tewksbury Lab

Research reviews by the Harvard School of Public Health’s Injury Control Research Center have concluded that more gun ownership leads to more gun violence.

Studies have found this at both the state and country level. Take, for instance, this chart, from a 2007 study by Harvard researchers, showing the correlation between statewide firearm homicide victimization rates and household gun ownership after controlling for robbery rates:

Social Science and Medicine

This holds up around the world. As Vox’s Zack Beauchamp explained, a breakthrough analysis in the 1990s by UC Berkeley’s Franklin Zimring and Gordon Hawkins found that the US does not, contrary to the old conventional wisdom, have more crime in general than other Western industrial nations. Instead, the US appears to have more lethal violence — and that’s driven in large part by the prevalence of guns.

“A series of specific comparisons of the death rates from property crime and assault in New York City and London show how enormous differences in death risk can be explained even while general patterns are similar,” Zimring and Hawkins wrote. “A preference for crimes of personal force and the willingness and ability to use guns in robbery make similar levels of property crime 54 times as deadly in New York City as in London.”

Guns are not the only factor that contribute to violence. Other factors include, for example, concentrations of poverty, urbanization, and alcohol consumption. But when researchers control for other confounding variables, they have found time and time again that America’s high levels of gun ownership are a major reason the US is so much worse in terms of gun violence than its developed peers.

Given that, it should come as no surprise that the research has also found that tighter restrictions on guns can prevent deaths: A 2016 review of 130 studies in 10 countries, published in Epidemiologic Reviews, found that new legal restrictions on owning and purchasing guns tended to be followed by a drop in gun violence — a strong indicator that restricting access to guns can save lives.

Some countries can testify to the success of gun control measures. In Australia, after a mass shooting in 1996, lawmakers passed new restrictions on guns and imposed a mandatory buyback program that essentially confiscated people's guns, seizing at least 650,000 firearms.

According to one review of the evidence by Harvard researchers, Australia's firearm homicide rate dropped by about 42 percent in the seven years after the law passed, and its firearm suicide rate fell by 57 percent.

Although it's hard to gauge how much of this was driven by the buyback program, researchers argue it likely played some role: “First, the drop in firearm deaths was largest among the type of firearms most affected by the buyback. Second, firearm deaths in states with higher buyback rates per capita fell proportionately more than in states with lower buyback rates.”

In short, more guns mean more gun deaths, and more restrictions on guns mean fewer guns and fewer gun deaths.

So while Clinton focused her debate response on toddlers — likely because that’s what her team figured would poll best — America’s gun problem really goes much further. It is this problem that DC was trying to address with its old law. And it’s this problem that the Supreme Court made all the harder to address by restricting how far governments can go in curtailing firearms.

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