■ An AP review found 30 mishaps with guns in schools since 2014.

They are the “good guys with guns” the National Rifle Association argues are needed to protect students from shooters: a school police officer, a teacher who moonlights in law enforcement, a veteran sheriff.

But in a span of 48 hours in March, the three committed gun safety lapses that put students in danger.

The school police officer accidentally fired his gun in his Virginia office, sending a bullet through a wall into a middle school classroom. The teacher was demonstrating firearm safety in California when he mistakenly put a round in the ceiling, injuring three students who were hit by falling debris. And the sheriff left a loaded service weapon in a locker room at a Michigan middle school, where a sixth-grader found it.

All told, an Associated Press review of news reports collected by the nonprofit

Gun Violence Archive revealed more than 30 publicly reported mishaps since 2014 involving firearms brought onto school grounds by law enforcement officers or educators.

“If this can happen with a highly trained police officer, why would we give teachers guns?” interim superintendent Lois Berlin of the Alexandria, Virginia, school system asked after the incident involving the officer whose accidental discharge put a bullet through a wall at George Washington Middle School.

But calls to encourage districts to add more armed educators and officers have intensified since the Feb. 14 shooting rampage at Marjory Stoneman Douglas High School in Parkland, Florida, which left 17 students and educators dead.

In March, the White House pledged to provide aid to state and local agencies to provide firearms training for school personnel and to recruit more veterans and retired officers into education. At least a dozen states have considered bills that would encourage more armed officers, security guards or teachers in public schools.

“It’s usually the person behind the gun who determines the outcome,” said Kansas state Sen. Dennis Pyle, a supporter of a bill that would have prohibited insurance companies from charging “discriminatory” rates to schools that arm their staff.