Like many politicians before him, Ohio Gov. Mike DeWine responded to a mass shooting in his state by calling Tuesday for a law that would take guns out of the hands of people deemed at risk of hurting people.

Such measures, known as red flag laws, have been passed in more than a dozen states in recent years, often in the aftermath of a gun massacre and often with bipartisan support. But while researchers say the laws hold promise, particularly in preventing suicides, there isn’t enough research being done to understand their effect on homicides ─ let alone mass shootings.

“Every time there is a question about preventing mass shootings, the answer always boils down to how to separate a potentially dangerous person from a firearm,” said Aaron Kivisto, a clinical psychologist at the University of Indianapolis who studies gun violence prevention. “Red flag laws are one important tool, but I don’t think you’ll find a single researcher who will claim that they are the panacea of gun violence. They’re not.”

Not enough is known about Connor Betts — the 24-year-old man who killed nine and injured 14 early Sunday in Dayton, Ohio, before being killed by police — to say whether a red flag law would have stopped him. But it doesn’t appear to be the case: Many of Betts’ former high school and middle school classmates said they had reported him to school officials for making a list of people he wanted to kill or rape, but that was years ago, and police said Betts had nothing in his background that would have kept him from buying the rifle he used in the attack.

Authorities said Tuesday that Betts had showed interest in violent ideologies and mass shootings but that it wasn't clear if anyone else knew about his plans.

Seventeen states have a red flag law on the books, with several more considering them. Most were passed after the Feb. 14, 2018, shooting at Marjory Stoneman Douglas High School in Parkland, Florida, that was committed by a former student whose threatening behavior had previously been reported to authorities by classmates, neighbors and social media followers.

The laws vary from state to state, and are also known by a variety of names, including extreme-risk protection orders and gun violence restraining orders. They generally allow police, friends and relatives to report someone they fear is at risk of imminently harming themselves or someone else. A judge may then decide to order police to temporarily seize the person’s firearms. The target of the removal can fight the petition, and if they lose, they can ask for the guns’ return after the risk of harm has passed.

Ohio’s Republican-controlled state Legislature hasn’t been welcoming to red flag laws; it rejected one proposed by then-Gov. John Kasich last year. But his successor, DeWine, who is also a Republican, said he has a different version that he hopes lawmakers will approve. DeWine first mentioned a proposal for "safety protection orders" in April, but highlighted it Tuesday as part of a range of proposals to reduce gun violence and improve mental health care.

“These orders, which will be granted upon clear and convincing evidence, would allow the removal of firearms from potentially dangerous individuals and get them the mental health treatment that they need, get them whatever help that they need,” DeWine said.

Red flag laws are the rare measures that people from either side of the gun debate seem to find palatable.

President Donald Trump and members of both parties in the Senate have expressed support for such laws; one Senate proposal would fund efforts to take guns from and help people deemed at risk of violence.

Gun-violence and public-health researchers generally support them as well. But those researchers also caution that the laws haven’t been around long enough to study how well they actually work.

Existing research has focused on Connecticut and Indiana, home of the country’s oldest red flag laws, dating to 1999 and 2005 respectively. Recent studies have shown that the laws are most often used to seize guns from people who are suicidal and that they have driven down the suicide rate by small percentages.

That alone is encouraging, researchers say, because most gun deaths in America are by suicide. But the impact of red flag laws on homicides and mass shootings remains unclear.

Despite the limited research, it makes sense to enact red flag laws, researchers say.

George Parker, an Indiana University professor who studies the impact of firearm seizure laws, said that from a public health perspective, eliminating the risk of gun deaths requires one of two things: removing guns from homes completely ─ which is unrealistic ─ or seeking “secondary prevention” methods that decrease the chances that guns will be used to kill people. That is where red flag laws fit in, Parker said.

“Why the emphasis on red flag laws? It’s something we can do,” Parker said. “If you have concerns about the number of firearms in the U.S. floating out there, you take what you can get in order to decrease the risk of the damn things.”

Red flag laws are separate from domestic violence restraining orders, which often can include requirements that the subject relinquish their guns. Those laws have been shown to reduce killings of romantic partners.

Joe Parks, medical director of the National Council for Behavioral Health, pointed out that many people who commit mass shootings leak their plans in some way. With the spread of red flag laws, that represents an opportunity ─ as long as people know the laws exist, and feel compelled to report someone they see as a risk.

The council published a report on mass shootings Tuesday, outlining causes and recommending ways to curb them. The report was originally supposed to be released in October, but was pushed out this week in response to last weekend’s attacks in Dayton and El Paso, Texas. The council recommended wide adoption of red flag laws, which it said could fit into a much wider public education campaign similar to the ubiquitous “see something, say something” anti-terrorism messaging.

“A lot of what is going to help mass violence is going to involve broad social changes on all our parts,” Parks said.

He added, “We need to be accountable for each other.”