Mourners gathered at a vigil on Wednesday outside the Walmart that was the scene of a mass shooting on Saturday in El Paso. (Luke E. Montavon/Bloomberg)
Jeffrey Swanson is a sociologist and professor in psychiatry and behavioral sciences at Duke University School of Medicine.

Laws that temporarily remove firearms from risky people have emerged as a rare point of agreement in the debate over how to stop mass shootings. Republicans, who have long resisted any measures that restrict access to guns, have joined Democrats in support: “We must make sure that those judged to pose a grave risk to public safety do not have access to firearms,” President Trump said in the aftermath of the El Paso and Dayton massacres, and “that is why I have called for red-flag laws.” Sen. Lindsey Graham (S.C.) said that “state red flag laws will provide the tools for law enforcement to do something about many of these situations before it’s too late.” Sen. John Thune (S.D.) said that he was “confident Congress will be able to find common ground on the so-called ‘red flag’ issue.”

These laws — formally called “extreme risk protection orders,” or ERPOs — allow concerned family members or law enforcement officers to ask a civil court for an order to remove guns for up to a year from people who are at imminent risk of harming themselves or others. Seventeen states and the District have enacted some version of an ERPO law, and the public broadly supports them.

But we cannot expect ERPOs to catch the next mass shooter or quickly halt the spate of public massacres. Or rather, if they do, it will be more by happy accident than design. Make no mistake: ERPOs do save lives. They’re just not likely to be the lives that fall to mass shooters. Certainly there is a logical argument for having them in place in the unlikely event that an alert citizen becomes aware of a rage-filled young man amassing a small arsenal to no good end. But as for solid scientific evidence that ERPOs can stop such killings, we’ll have to wait for that — perhaps for a long time. As it happens, the people who benefit most are the ones planning to kill themselves.

The evidence on suicide prevention is a good enough reason for states to enact ERPOs and for the federal government to incentivize them with infrastructure grants. In Connecticut and Indiana, researchers like me found that for every 10 to 20 gun-removal actions under such laws, one life was saved through an averted suicide. In almost every state where an ERPO bill has passed, lawmakers were responding to a public outcry over a horrifying mass-casualty shooting. But it is mostly suicide concerns that have prompted their use in practice. Suicidal thoughts and behavior are common in the population; mass shootings are not. More than 1 million Americans attempt suicide each year, and 47,173 of them died in 2017. By comparison, in the same year there were 11 public mass shooting incidents, claiming 117 lives (58 in the Las Vegas Strip massacre alone).

An ERPO can also accomplish what point-of-sale gun restrictions in many cases cannot. Most people in a suicidal crisis can legally possess guns and would pass a background check if they tried to buy a firearm. ERPOs don’t require the kind of record that would prohibit a sale — just behavioral indicators of risk as defined in the law, documented by police officers and endorsed by a judge.

Here is how an ERPO is most likely to work: You find out that a member of your family is feeling suicidal and has guns. You can make a call that sets in motion a legal process to separate those guns from your loved one for a while — an action that could save that life.

But here is how an ERPO could also work, in a far less common but no less concerning situation: You become aware that there is someone with guns who is behaving in an obviously dangerous or threatening manner, and you call the police to investigate. In an ERPO state, the police won’t have to wait until a crime has been committed. With probable cause, they can seek an expedited civil court order from a judge allowing them to search for, and remove, the risky person’s firearms. Later, after the guns are secured, a court hearing is held — typically within 14 days — to determine whether it is safe to return the individual’s firearms or, if not, to order that the guns be retained for up to a year. Due process is baked into ERPOs from the beginning, and no criminal record is produced at the end.

The gun-removal subjects in Connecticut and Indiana were at least 30 times more likely to die of suicide than other adults in the general population, according to death-record searches by our research group. Most of these suicides involved methods other than guns, or occurred after a year had passed and the person became eligible to have their guns returned. This pattern showed us that ERPOs were being applied to a population in true need of intervention, not used willy-nilly. Such a risk-selection process happens naturally, because people in a suicidal crisis often give signs that alarm family members or friends. If population-based screening for suicidality is like trying to find a needle in a haystack, ERPOs provide a very small haystack with many needles in it.

Of course, one of those “needles” could also be a potential mass killer. The more ERPO laws are scaled up, and the more firearms are removed from dangerous people, the more likely it becomes that at least some mass shootings will be averted in this way. We may never know when; we won’t see a big headline announcing what did not happen. But if mass shootings gradually decline as ERPOs are broadly implemented across the country, what will matter is that fewer people will die in senseless rampages; the why and how are less important.

Meanwhile, reducing suicides by gun — 23,854 in 2017 — is an important public health goal in its own right. ERPOs can help us get there, in at least two ways. When police officers serve a “risk warrant” to separate guns from someone, they often encounter a person in crisis. After removing any guns, officers typically transport the individual to an emergency room for evaluation, where the person may be admitted for inpatient psychiatric care and then referred to outpatient follow-up. In our Connecticut study, the proportion of gun-removal subjects who were receiving outpatient mental health treatment doubled from the year before to the year after guns were removed — to about 24 percent from 12 percent. This alone could have saved lives; for some, gun removal was a doorway out of a dark place.

ERPOs can also prevent suicides by limiting access to the most lethal method of self-injury. People who try to end their lives by other means usually survive; if they use a gun, there is almost never a second chance. This is why a mere shift in the distribution of suicide methods — away from guns to more survivable means — could save many lives. If ERPOs were to be passed in every state, far fewer suicidal people would have their hands on a gun in a moment of despair. And far fewer would die. As an added benefit, once these laws are in place, they provide a practical means of action in those rare instances when a would-be mass shooter telegraphs his intent.

Psychiatrists cannot reliably identify potential mass killers by screening their patients. This kind of severe violence is too rare for that, and the many risk factors for it are too nonspecific. Besides, most mass killers aren’t seeing psychiatrists in advance. But an ERPO could stop such a person, without infringing on the rights of legitimate gun owners who don’t threaten anyone. Broadly implementing ERPO laws is just one piece in the complex puzzle of gun violence prevention in the United States. But as a place to start, it could bridge the divide between gun-control advocates and those who insist that it’s people, not guns, who kill.

Read more from Outlook:

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You can’t stop mass shootings by punishing people with mental illnesses

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