This post was first published on Feb. 15. It was updated on May 18.

BERLIN — Contrary to what you may sometimes hear, school shootings are not unique to the United States. Germany, for instance, went through a string of devastating attacks between 2002 and 2009. Between 1996 and 2008, major school shootings also occurred in Finland and Scotland, among other places.

But in Europe, there hasn't been a major high-casualty gun attack on a campus in almost a decade.

Meanwhile, Friday's high school shooting in Galveston County, Tex., was far from being the first this year in the United States. It came just three months after a gunman in Parkland, Fla., shot and killed 17 people at a high school. In response to that attack, some states toughened gun laws, while companies and major businesses scrapped their ties to the National Rifle Association (NRA).

There is widespread consensus in Europe and abroad that some school shootings are impossible to prevent. But the numbers still show that there are some things countries can do, and Europe appears to have learned from uncomfortable lessons while U.S. lawmakers still hesitate — especially on a national level.

The prevalence of handguns

The most frequently cited reason that mass shootings — not necessarily in schools — are more frequent in some countries than in others is the prevalence of firearms. In his famous study, “Public Mass Shooters and Firearms: A Cross-National Study of 171 Countries,” University of Alabama criminology professor Adam Lankford found a link between the number of guns and mass shootings that killed four or more people. The data set ranged from 1966 through 2012.

The study indicated that a decrease in the number of weapons also would probably result in a decrease in shootings. That’s exactly what happened in Australia after the country tightened gun legislation following a mass shooting in 1996. It would also explain why countries where gun ownership is rare, such as France or Britain, have largely been spared such catastrophic incidents.

Apart from arguing that Lankford’s overall data set is misleading because it doesn't take into account politically motivated violence, critics also questioned whether the number of weapons is really the most significant factor. They point to one nation in particular: Switzerland.

Access as the key factor?

Switzerland has one of the world’s highest ratios of firearms per person, with an estimated 45.7 guns per 100 residents, according to the Small Arms Survey. Only two countries have a higher ratio: Yemen, with 54.8 guns per 100 residents, and the United States, with 88.8 guns per 100 residents. Other studies have even indicated that the share of households with weapons may almost be the same in Switzerland as it is in the United States. Those statistics have big margins of error, but they still point to a legitimate question: Why has there never been a school shooting in Switzerland, despite the Swiss enthusiasm for weapons?

With about 8 million citizens, Switzerland is, of course, much smaller than the United States. But it’s still more populous than Finland, a European country that has fewer weapons but more school shootings.

Many of Switzerland’s weapons are distributed to citizen soldiers, as they are known. Conscription is mandatory for male Swiss citizens, and conscripts can keep their semiautomatic assault rifles at home even after returning to their nonmilitary careers. (They still have to report for a short annual training). Meanwhile, those who wish to buy weapons themselves need to undergo a weeks-long background check.

Swiss authorities have a list of about 2,000 individuals they suspect of being willing to commit shootings. All of them are frequently approached by authorities, along with psychologists, and are forced to hand over their weapons immediately or are barred from purchasing new ones.

Some sociologists say that Switzerland's military service comes close to an extended background check, too, and that the country's education system teaches children early on to search for compromises instead of risking open conflicts. Hence, while almost every home in Switzerland may have a weapon, access is still indirectly regulated, and the use of weapons usually follows strict societal norms.

There’s also another crucial difference with the United States: extensive, mandatory health insurance, which allows schools to have direct and immediate access to psychologists and intervention teams.

Growing awareness of the need of psychological support

Similar measures are still being implemented in Germany, the nation with the most school shootings in contemporary European history. Following a string of attacks, the country tasked a number of academics and professionals to come up with guidelines how to spot potential attackers early on.

When President Trump took to Twitter after the Parkland shooting in February, he urged students and others to alert authorities to anyone whose behavior struck them as suspicious. “So many signs that the Florida shooter was mentally disturbed, even expelled from school for bad and erratic behavior,” Trump wrote in the tweet. “Neighbors and classmates knew he was a big problem. Must always report such instances to authorities, again and again!”

But experience from abroad shows that awareness alone may not be sufficient. Other countries, including Germany, have attempted to set up government-led national networks dedicated to spot potential attackers and to stop them before they can pursue their plans.

In a first step, funding for in-school psychologists was increased exponentially. Teachers at every school are now being trained to act as “trusted personnel,” as a first point of contact either for students who want to seek psychological support themselves or for others who want to raise alarm over the behavior of an individual. Psychologists are then called in to examine each case further.

Psychological tests are also standard practice for Germans younger than 25 who want to purchase firearms. Age restrictions were tightened, and a national registry of all weapons was created in 2013.

This hasn’t stopped other attackers, such as a 2016 right-wing shooter who killed nine people in Munich’s city center, from obtaining weapons illegally online. Even the best prevention programs, government experts here agree, won't provide 100 percent safety — but they offer a more comprehensive solution than what the White House has so far proposed.

Agreement that teachers shouldn't be armed

When Trump invited some of the survivors of the Parkland school shooting to the White House in late February, one idea he supported was arming teachers. The president later doubled down on  the proposal in several tweets. “Highly trained, gun adept, teachers/coaches would solve the problem instantly, before police arrive,” Trump wrote, referring to armed teachers. With such measures in place, he said, “ATTACKS WOULD END!”

Experts who have spent years successfully trying to prevent similar shootings in Europe on behalf of their governments quickly rejected the idea.

Herbert Scheithauer, one of Germany’s primary experts on the issue and a psychology professor at Berlin's Free University, warned that arming teachers could lead to more violence, as some students already at risk of committing a shooting may see the armed resistance as a challenge.

“Based on academic research, we know that the presence of firearms can trigger dangerous reactions among certain people. Instead of deterring them, weapons may actually trigger violent fantasies,” Scheithauer said.

“Given that there are such great concepts to prevent school violence in the first place, I really don’t understand why the idea of arming teachers is discussed so prominently, even though we still don’t even know whether it would have a positive impact or lead to the deaths of even more students,”  Scheithauer said about the U.S. debate on school shootings.

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