Every day seems to bring a new tragic story of a person with serious mental illness killed by police. In Seattle, for example, there were recently back-to-back deaths: a 30-year-old pregnant woman shot in front of her children, and a 20-year-old man killed right before his high-school graduation during what appeared to be his first psychotic episode, with a pen in his hand police mistook for a knife. Sometimes, the consequences are not death but violent confrontations, arrests, and incarceration—occurring only because of miscommunication, missed signals, and misunderstandings.

Most of these tragedies result from officers’ lack of training on how to deal with people with serious mental illnesses. Standard police training—to issue commands, and when they are not followed, to push harder and more aggressively—may work in other circumstances, but are exactly wrong for those with mental illnesses or developmental disorders.

The awful consequences of these encounters—injured police officers; people dead or imprisoned unnecessarily; families grief-stricken and bereft; and wrongful-death lawsuits against cities, towns, or counties that result in large settlements paid by taxpayers—are bad for all.

For those making policy to ameliorate problems, there is a typical dilemma. Saving lives usually means spending a lot of money. Saving money can often mean losing or damaging lives—the current debate over health policy underscores that set of tradeoffs. Rarely do we find a policy option that both saves lives and saves money. But that option is here for this immense problem. It is called crisis intervention team training, or CIT, and it works—there’s data, and results, to prove it.

Miami-Dade County is a behemoth; it’s the seventh most populous county in the United States, with over 2.7 million people in 34 incorporated cities and towns. It also has the highest concentration of those with serious mental illnesses in the country: 9.1 percent of the general population, which translates to 192,000 adults and 55,000 children. Seventeen years ago, Miami-Dade experienced the same kind of violent encounters on a regular basis that we see reflected in the news today. There was, on average, one death a month stemming from interactions between police and residents with these illnesses, along with about 20,000 arrests and incarcerations each year.

Yet since 2010, the two largest police agencies, the City of Miami and Miami-Dade County police, have handled 71,628 mental health-related calls—and have made only 138 arrests. Miami-Dade taxpayers were on the hook for millions of dollars from wrongful-death lawsuits; today, fatal shootings are down almost 90 percent. More than 20 percent of those in county jails had serious mental illnesses, costing many millions to keep them there. Recently, the decline in arrests and incarcerations enabled the county to close a jail and save taxpayers $12 million a year.

What changed? A comprehensive program to structurally transform the way the community responded to people with mental illnesses (which Miami-Dade County Judge Steve Leifman, one of the authors of this piece, initiated). A key component was the CIT training of over 5,400 police officers in Miami-Dade, representing all 36 police departments, using a 40-hour program crafted initially in Memphis, Tennessee, in the late 1980s. To be sure, it was not easy. First, many police officers believe they know what they are doing and don’t think they need additional training. Second, it was a battle to convince police chiefs to take their cops off the beat for a week to take the course.

Aided by a grand-jury report investigating the criminalization of people with mental illnesses by the local state attorney, Katherine Fernandez Rundle, the program took off. Police dragged reluctantly into the program became believers—especially after they saw the results firsthand when they went back onto the streets. Most officers don’t seek confrontation; they prefer peaceful resolution of incidents or disputes. As Miami-Dade Police Director Juan Perez put it, “Our police department understands and believes that treatment over arrest for the mental-health population provides better, long-lasting results.”

Additionally, the program uncovered one of the least-discussed problems in the world of policing: the high incidence among police of depression and suicide, usually twinned with post-traumatic stress disorder. Every day, officers go out into a world where there is danger—where they might be shot and killed during a routine traffic stop, sitting in their cruiser (as in New York recently), or during a confrontation with violent criminals. Sometimes, they are military veterans with PTSD joining or re-joining police departments.

But the culture in the police world is not to acknowledge fear, stress, or weakness—and if officers do, they can be pulled off the street and put on a desk. Police who are suffering or dealing with PTSD may be more prone to hair-trigger reactions, which in turn can mean more tragedies. Those who’ve gone through the Miami-Dade program have been more willing to recognize their own stress and to seek help. Around 150 CIT-trained officers each month reach out to the program’s coordinator for mental-health advice and treatment for their own traumas.

So CIT saves lives and saves money. But it takes money up-front to save both. And that is not so easy. There is the cost of the training itself; while Miami-Dade has allocated money for it, other jurisdictions are not so willing to do so. Efforts in the past two Congresses to expand CIT for police—as well as for prison guards, school security, and others—have gotten nowhere. Then there are the other ancillary costs required to replicate the outcomes of Miami-Dade. For many of those with serious mental illnesses who encounter police, the appropriate place for them to go is a mental-health facility, not a jail. Beds, in good facilities, are in short supply everywhere in the country.

At the same time, finding treatment for people with these illnesses, including medical care and often a place to live, usually requires Medicaid. In Miami-Dade, the program has done so well that both the county and the conservative Florida legislature have appropriated funds to build a new comprehensive treatment center for the most acutely ill, who regularly recycle through both the criminal-justice and mental-health systems. Most states and counties have failed to invest in expanding the number of beds available to residents overall, much less invest in quality treatment facilities. And, of course, there is a battle in Congress over whether to drastically alter Medicaid, which would have disastrous effects on people with mental illnesses, jail populations, and the criminal-justice system as a whole.

Ideas that transcend our tribal and polarized politics are in short supply. CIT is one of those—one that deserves and needs to be financed and expanded.