Over nine days in July, the first class of school marshals gathered for training. The group of seven teachers and administrators, largely male, assembled at eight each morning at Tarrant County College’s Criminal Justice Training Center, in northwest Fort Worth, to discuss tragedies like Columbine, Virginia Tech, and Sandy Hook. They parsed the details and talked about how they would theoretically respond to such an emergency.

By the seventh day of training, the group had moved to the facility’s fifty-yard indoor shooting range. It was there that they were learning how to use deadly force in the event of a school shooting. Wearing T-shirts, jeans, and lime-green ear muffs, they stood with their legs apart, pointing their guns at white paper targets as the thunderous popping sounds of gunshots bounced off the concrete floor, walls, and ceiling. Seasoned cops wearing bright-red shirts managed the drills.

After lunch, they practiced shooting on the move, an advanced skill that few civilians learn but is standard practice for police and military. Several of the men darted from side to side, their arms outstretched and their fingers clenched around Glock and Sig Sauer pistols. Some crisscrossed their feet in the style of a football player, and the instructors encouraged them to shuffle, to decrease the risk of tripping. Some held their breath in concentration, and an instructor noticed. “This is not underwater shooting!” he shouted above the din.

Rafael Perea, the instructor in charge of the training, paced behind them, offering suggestions only when everyone had stopped shooting and the noise died down. The students had been mostly calm and collected, and Perea was impressed with their progress. However, he had been surprised to find some of expressing anxiety before their first shooting exercise. Though they had all shot guns at firing ranges before, this was different since more than ten journalists with big cameras and flashing lights were there to cover the event.

“I heard from some of the guys that they were nervous,” Perea said with a grin, a teacher excited to have challenged his students. “But that’s good, because if you talk about what they’d go through in real life, there would be stress.” The feeling of being on camera, he said, is the only kind of stress I can give to them.

That was not exactly the case. The next day, they would be acting out a shooting scenario at a local school using detergent pellets instead of bullets. And Perea had found other methods of creating stress under artificial conditions: instead of the circular targets or vague human outlines you’d see at many shooting ranges, he had posted up pictures of suspects from recent mass shootings. The white sheets of paper getting ripped apart by the trainees’ bullets featured human faces, some of who were teenagers.

When asked about these targets, Perea paused. His tone suddenly shifted from friendly to solemn. His grin disappeared. I don’t want someone to hesitate just because the shooter is a young person, he said. “We’re not used to shooting people, much less a child.”

Perea then put on his earmuffs and walked back into the firing range.

In early 2013, the Texas Legislature passed the Protection of Texas Children Act, which gives districts the option of arming and training one school employee, known as a “school marshal,” for every four hundred students. The trainees who assembled at Tarrant County College more than a year later were the first official school marshals, sent by districts taking advantage of the new law. They will function as peace officers, authorized to act only “under circumstances that would justify the use of deadly force.” Their identities are kept secret from students and the public.

The new law expanded the practice of arming public school teachers; some districts had already been doing so for years. In 2007 the Harrold Independent School District—a tiny district of one hundred students located 175 miles northwest of Dallas—responded to the Virginia Tech shooting by creating the “Guardian Plan,” which designates certain teachers, or “guardians,” to carry concealed handguns. David Thweatt, the school’s superintendent, told reporters that he’d enacted the plan because the district was 30 miles away from the nearest law enforcement. A handful of rural districts around Texas called Thweatt for advice and started similar programs.

These guardian plans received little attention until the 2012 shooting at Sandy Hook Elementary School. In much of the country, the tragedy of twenty murdered children spurred anti-gun activists to push for gun control measures, but in Texas and a few other states—like Arkansas, Georgia, Idaho, and Colorado—the response was the opposite. Parents and teachers reasoned that armed teachers, administrators, and even college students might help to kill a mass shooter before the police were able to arrive. Some months after the shooting, a gun store in Austin started offering discounts to teachers.

As the Texas Legislature geared up for their 2013 session, newly elected state representative Jason Villalba, a Republican from Dallas, began arguing that the current guardian plans were not enough and that armed school employees needed police-style training. The bill faced plenty of critics, including some officers. The police chief of Dallas ISD said he questioned the wisdom of placing teachers in a situation that would be challenging for even the most experienced law enforcement. Others worried that a teacher with a gun might be mistakenly shot by responding officers.

Still, the bill passed easily (123 to 22 in the House, 27 to 4 in the Senate) and was signed into law by Governor Rick Perry, making it the second law in the country to explicitly allow teachers to carry guns (South Dakota, earlier that year, became the first).

This past April, after questions surfaced about whether the Guardian Plan potentially conflicted with the Marshal Plan, Attorney General Greg Abbott issued an opinion that both programs were allowed, and now districts can choose between these options. Villalba’s school marshal program is actually more restrictive than the disparate concealed-carry policies that came before it, which differ from district to district and, to be legal under the Texas Education Code, only require some “written regulations” created by that particular district.

Whereas Harrold ISD’s guardians simply obtain approval from the school board after proving they have a concealed-carry license, prospective school marshals must take the same psychological exams given to police officers. They are asked to confront whether they’d be comfortable shooting an intruder. They are given police-style instruction in active shooter response strategies. And if the school marshal is a teacher, as opposed to a principal or secretary, he or she must keep the gun in a locked safe within “immediate reach.”

That last requirement has proved unpopular. Muleshoe ISD, in the Panhandle, decided against implementing the program, and their superintendent, Gene Sheets, told the Lubbock Avalanche-Journal it was because the locked box requirement would prevent teachers from responding quickly enough. It remains to be seen whether more districts will choose Villalba’s school marshal program, with its psychological testing and intensive training, or Harrold ISD’s guardian plan, which doesn’t mandate a locked safe and which gives districts more discretion in what they require of armed teachers. In a letter to Abbott, state representative Joe C. Pickett, who chairs the House Committee on Homeland Security and Public Safety, noted that because of these “stringent requirements,” many school districts are expected to choose the less intensive guardian plan.

But whichever program districts choose, Villalba’s law has undeniably led a wave of districts to more actively consider the idea of arming employees and has prompted public support. In Spring, a suburb of Houston, a firearms instructor named Chuck Persinger is offering free concealed-carry classes to teachers (many of those taking the class, he noted proudly, are women). In January 2013, when Villalba’s bill had been announced but had not yet passed, Alan Spence, a retired peace officer and law enforcement instructor, started the Texas School Marshal Academy, in Giddings. He offers classes to teachers and school administrators about what to do in a shooter situation, even if they are not armed, to minimize deaths and injuries. “We can’t wait on a cop to get there,” Spence told me. “These teachers need to have the opportunity to protect themselves, and knowledge is key in any tactical situation.”

Perea spent more than a decade as a police officer in Abilene and several years in the Air Force police, but for the past twelve years he has been a full time gun safety instructor. He displays the cheery solicitousness you might associate with a teacher more than a cop. Watching the marshals in Fort Worth fire at targets on the other side of soundproof glass, he explained how each school shooting has produced lessons for law enforcement. Because the Columbine shooters in 1999 took the unprecedented step of using explosives, the marshal curriculum includes steps for how to handle a bomb on school grounds. The Virginia Tech shooting taught police to be prepared for a shooter who chains the school doors shut. Since the Sandy Hook shooter gained entry to the school by shattering the windows, some districts are now purchasing thicker, stronger glass.

Many of the lessons taken from these mass shootings are less about how to react in the moment than they are about what criminologists and cops call “crime prevention through environmental design.” Perea hopes that in addition to the school marshals’ ability to respond to a crisis situation, they will provide expertise on how to institute preventative measures as districts build new campuses and update existing ones.

Still, Perea said it is often impossible to predict the particular horrors of school shootings that may occur in the future.   As an example he cited Jonesboro, Arkansas, where, in 1998, two middle school students pulled a fire alarm and then hid in a wooded area near the school entrance, shooting at kids and teachers as they filed out. Nobody could have really been ready for that, Perea told me.