The national debate over gun control has reached something of a breaking point in Congress since Omar Mateen killed 49 people at a gay nightclub in Orlando earlier this month. Sen. Chris Murphy (D-CT) led Senate Democrats in a 15-hour filibuster last week until Republicans would agree to take a vote on gun control measures. Rep. John Lewis (D-GA) led Democrats in a sit-in on Wednesday to make the same basic demands.

These efforts are probably doomed to fail, at least in the short term. But it’s still worth discussing the actual policies that Democrats are willing to halt congressional business in order to demand votes on.

The most prominent, and most controversial, proposals seek to ban people suspected of terrorism from buying guns — for instance, by turning the no-fly list into a “no-gun list.” But the problem with these ideas, many critics argue, is that they would probably violate people’s due process rights and set a dangerous precedent — especially for Muslims who are more likely to be racially profiled.

To be clear, actually solving America’s gun problem would take much more radical action than Congress seems willing to contemplate. But there are better and worse ways to try to at least reduce the likelihood of gun violence.

So here’s an idea. If we don’t like egregious civil liberties violations, but we still want to curb mass shootings by banning certain people from owning guns instead of banning guns themselves, we shouldn’t focus on suspected terrorists. We shouldn’t focus on people with mental illnesses either, since there’s no good evidence that this would help.

We should focus on domestic abusers.

Many high-profile mass shooters are also domestic abusers, and most “mass shootings” are actually domestic violence incidents

After Omar Mateen was identified as the perpetrator of the worst mass shooting and most deadly anti-LGBTQ hate crime in modern US history, his ex-wife told the media that Mateen had violently abused her during their brief marriage in 2009. Mateen's former co-worker Daniel Gilroy said that Mateen “did not like women at all,” and had a temper that was "scary in a concerning way."

But Mateen is far from the only high-profile mass shooter who has a history of alleged domestic abuse, as Jennifer Mascia reported for the Trace in December.

There was Robert Lewis Dear, the alleged Planned Parenthood shooter in Colorado Springs, who was never convicted of a sex crime but who was accused of sexual assault, domestic violence, or stalking by three different women, including his then-wife. There was John Houser, who killed two and injured nine in a movie theater in Lafayette, Louisiana, whose wife and daughter filed an order of protection against him for domestic violence. There was James Huberty, who killed 21 people at a California McDonald’s in 1984 and whose wife reported him to police for giving her a "messed up" jaw. The list goes on.

Mass shootings are so scary because they seem so unpredictable. They can happen anywhere and to anyone, and they are often carried out by men who have no criminal history that could have prevented them from buying a gun in the first place.

But in fact, the majority of what could be called "mass shootings" are all too predictable — and many victims are the women and children who find themselves entangled in the lives of violently abusive men.

More than half of mass shootings (defined as a shooting in which at least four people are killed with a gun) involve a current or former intimate partner or a family member. Most of the victims of those shootings, 81 percent, are women or children. And 70 percent of all mass shootings happen inside the home, not out in public. These shootings make the local news, but they are both so private and so sadly routine that they almost never get the massive national attention that rarer public shootings do.

"Men who commit violence rehearse and perfect it against their families first," wrote Pamela Shifman and Salamishah Tillet in a New York Times op-ed in February. "Women and children are target practice, and the home is the training ground for these men’s later actions."

Domestic violence is a screaming red flag for future violent behavior, but keeping guns away from abusers isn’t always easy

"We know that violence is the best predictor of future violence," said Shannon Frattaroli, an associate professor at the Johns Hopkins Bloomberg School of Public Health who researches the connection between gun violence and domestic violence. "If someone has demonstrated past violent behavior, it's probably the best indicator we have of the risk of being violent in the future."

Domestic violence in particular is extremely predictable. It’s common for police to be called multiple times, sometimes dozens, for domestic violence incidents before a victim is ultimately murdered by her abuser. Recidivism rates for domestic abusers are high. And a substantial body of research shows that victims of domestic violence, particularly women, are put at much greater risk of being murdered when a gun is involved.

So if we care about protecting victims, there’s already a lot of incentive to get guns out of the hands of domestic abusers. And indeed, there are already some laws in place to do this. Federal law prohibits the sale or possession of guns for anyone convicted of a domestic violence misdemeanor, or anyone who is subject to a domestic violence restraining order. Some states have laws that allow or require law enforcement agents to seize any guns found at the scene of a domestic violence incident.

But not all states have the same laws, and federal law has significant limitations. Non-married partners who don’t live together are not protected, nor are family members other than children. It helps that federal law covers misdemeanors and restraining orders, since it’s difficult to get a felony conviction for domestic violence. But federal law only covers a full restraining order — and victims face the highest risk for violent retaliation from their abusers after an initial temporary restraining order is granted, and that comes before a full order.

Implementation is also a huge barrier to taking guns away from domestic abusers, Frattaroli said. It takes a lot of action from law enforcement to actually take away someone’s gun after he has been served with a domestic violence restraining order.

First, police officers have to know that an abuser owns a gun in the first place — and data on that can be spotty because not every state has a gun registry or gun sale database, and not all of those databases are complete. Then an order has to be served, which requires actually finding the offender. And then law enforcement actually has to go about seizing the firearm.

“There are some places that are doing some great work to implement and enforce these laws,” Frattaroli said. “But my sense is it's not routine, it's not commonplace, it's not what is happening across the country on a systematic scale.”

Plus, for new gun purchases, background checks still aren’t universal. So it’s very possible for someone who is subject to a domestic violence restraining order — temporary or otherwise — to get a gun even if he isn’t legally supposed to.

What might good policy solutions to this problem look like?

Frattaroli and her colleague April Zeoli laid out a list of policy recommendations in the book Reducing Gun Violence in America.

One key recommendation is universal background checks — another major proposal that congressional Democrats have been pushing in their filibusters and protests. This would help solve the implementation problems mentioned above.

To further beef up implementation efforts, Zeoli and Frattaroli recommend establishing a federal training program to help state and local law enforcement agencies do a better job of enforcing the laws that already exist. They also say we should give states incentives to create gun registries, and to automatically update their background check systems as new domestic violence restraining orders and misdemeanor convictions come in.

Perhaps the most intriguing suggestion Frattaroli mentioned, though, is something called a gun violence restraining order. California became the first state to pass a law like this in 2014.

Much like a domestic violence restraining order, a gun violence restraining order gives a concrete, emergency legal step for victims or concerned family members to take if they know that someone close to them is dangerous. They can petition the court to prohibit the person from buying or possessing a gun for a defined period of time; a year, for instance.

The basic idea behind this policy is that family members and friends of an abuser, as well as law enforcement officers who answer their distress calls, are on the front lines of abuse. They are the most likely to know if a person has a pattern of violent behavior, and they are most likely to suffer from it. Yet unless someone has committed a crime or can be involuntarily committed to a mental institution, there’s not much anyone can legally do to keep guns out of his hands.

Omar Mateen was known to have a violent temper by more than one person in his life. The parents of Jared Loughner, who shot Rep. Gabrielle Giffords and killed 10 people in Tucson, Arizona, in 2011, knew he was violent and took away his shotgun but couldn’t do anything more unless he had committed a crime or unless they had decided to try to have him involuntarily committed to a mental institution. The family of Elliot Rodger, who went on a misogynistic killing spree in Santa Barbara, California, in 2014, was similarly worried about his threatening behaviors and similarly powerless to do much about it.

Of course, not all "mass shooters," as the media popularly imagines them, have a previous history of domestic violence, or of violent and erratic behavior that’s bad enough to make family members worried. But many of them do. And, again, most "mass shootings" aren't how we imagine them — they’re not school shootings or dance floor massacres. They’re relatively private acts of horror, preceded by red flag after red flag of abusive and violent behavior.

We can’t predict who will become a mass shooter, nor can we save every potential victim of domestic violence. But it would be an unforced error not to do all we can to keep guns out of the hands of people who are known to be violent — and it’s a lot easier to predict violent behavior in general than the specific decision to commit a mass shooting.