The opinions expressed by columnists are their own and do not necessarily represent the views of Townhall.com.

Another school shooting, this time by a 15-year-old at Saugus High School in California, another quest for answers. Yet, 20 years after Columbine, the United States is still looking for how to stop mass public shootings. The rest of the world, where mass public shootings are actually much more common, is also looking for solutions. Russia, France, Finland, and Norway are among the European countries that have experienced far more deaths per capita from these attacks.

Change is coming, if slowly, in the United States. Earlier this year Florida and Texas passed major improvements to their laws that are significantly increasing the number of teachers with guns at school. Both bills received strong support from those states’ Republican governors.

Florida’s bill removed a limitation that only allowed non-classroom-based teachers to defend the classroom. Texas removed the cap on the number of school personnel that can carry firearms at schools.

It isn’t by coincidence that every mass public shooting in Europe since at least 1990 has occurred in an area where general, law-abiding citizens are banned from carrying firearms for protection, and for recent mass public shootings in New Zealand, Brazil, and the Netherlands. That has also held true for 94% of such attacks in the U.S. since 1950.

Moms Demand Action, a gun control advocacy group funded by Michael Bloomberg, argues that the bills in Texas and Florida “would make school a much more dangerous place for our children.” By contrast, President Trump keeps proposing arming teachers and staff at schools, saying: “I’m telling you that would work.”

But 20 states currently allow teachers and staff to carry guns to varying degrees on school property, so we don’t need to guess about how safe these schools are. Some states have had these rules for decades. In recent decades, only California and Rhode Island have moved to be more restrictive. The Crime Prevention Research Center, of which I am the president, has just released a new report looking at all the school shootings of any type in the United States from 2000 through 2018.

During these years, Utah, New Hampshire, Rhode Island, and parts of Oregon allowed all permitted teachers and staff to carry, without any additional training requirements. Other states leave it to the discretion of the local superintendent or school board. As of December 2018, teachers carried in more than 30 percent of Texas school districts. And in September 2018, Ohio teachers were carrying in over 200 school districts.

Roughly 5 percent of Utah teachers carry permitted concealed handguns at school, according to Clark Aposhian, the senior member of Utah's Concealed Firearm Review Board. Support staff — including janitors, librarians, secretaries, and lunch staff — carry at a higher estimated rate of between 10 and 12 percent.

Carrying in a school is no different than in a grocery store, movie theater, or restaurant. Seventeen million Americans have concealed handgun permits — which is 8.75 percent of the adult population outside of permit-unfriendly California and New York. Nobody knows whether the person next to them might have a gun, unless it happens to be needed.

We found 306 cases of gunshots on school property, 48 of which were suicides. Not counting suicides, 193 people died and 267 were injured in these incidents. Four cases were simply instances of accidental gunshots by police officers.

The rate of shootings and people killed by them has increased significantly since 2000. The yearly average number of people who died between 2001 and 2008 versus 2009 and 2018 has doubled (regardless of whether one excludes gang fights and suicides).

This increase has occurred entirely among schools that don’t let teachers carry guns. Outside of suicides or gang violence in the wee hours of the morning, there has yet to be a single case of someone being wounded or killed from a shooting at a school that allows teachers and staff to carry guns during school hours. Indeed, the one shooting occurred at 2:20 AM in a parking lot when no armed teachers would have been around.

There haven't been any serious accidents. No student has ever got a hold of their teacher’s gun, and the one accidental discharge by a teacher occurred outside of school hours. The teacher had only very minor injuries.

School insurance premiums haven‘t risen at all from teachers being allowed to carry. “From what I’ve seen in Utah, [school insurance] rates have not gone up because of guns being allowed,” says Curt Oda, former president of the Utah Association of Independent Insurance Agents. Nor has a survey of six other states shown any increase in insurance costs.

Police are important, but they can't be everywhere at once. Even if an officer is stationed at the school, mass public shooters are most likely to target the officer first. We’ve seen this time and again at malls, nightclubs, and schools. This also makes the job of the police much safer. Concealed carry means that killers won't know who is armed. Even if they take an officer by surprise, they must worry that they are revealing their position to someone else who can stop them.

Not a single person has been injured or killed by a teacher’s gun. But even more amazing, not a single person has been shot during school hours. Gun control groups may paint fearful pictures of what might go wrong with teachers carrying, but that fear gets harder to push given these programs’ successes. This research provides evidence that armed teachers deter attacks.

It is past time for us to do something that really works. With another mass public shooting in California, it is time for California to recognize that its gun control laws might actually be part of the problem. Let’s stop leaving our schoolchildren as sitting ducks.

* Lott is the president of the Crime Prevention Research Center and the author most recent of “The War of Guns.”