A makeshift memorial outside the Marjory Stoneman Douglas High School...

A makeshift memorial outside the Marjory Stoneman Douglas High School in Parkland, Florida, where 17 students and faculty were killed in a mass shooting on Feb. 19. Credit: AP / Gerald Herbert

The massacre at Marjory Stoneman Douglas High School in Parkland, Florida, makes it clear that we must do far more to ensure schools are safe.

And there are a number of steps we can take right now — including ensuring mental health services are widely available; staffing schools with well-trained resource officers, who may be armed if a community so decides; instituting wider background checks; and banning military-style assault weapons and munitions.

But one idea that just won’t work is arming teachers, as President Donald Trump suggested this week.

Educators’ first instinct is to protect kids, not engage in a shootout that would place more children in danger. This good-guy-with-a-gun thinking might give some people the illusion of security, but it only would make our children’s classrooms less safe, and turn our schools into armed fortresses.

Decades of grim data show that having guns at home greatly increases the chance of them being used in a homicide, suicide or accidental death. The United States has both the highest gun ownership and the highest gun death rate in the Western world, though the states with the strictest gun ownership laws have the lowest rates of gun deaths.

Introducing guns in schools carries additional risks, and raises pertinent questions.

How would arming teachers work? Would teachers carry guns in holsters, or would every classroom have a gun locker? Would teachers be expected to regularly recertify, as required of many armed professionals? Are teachers to get their guns or get their students to safety with seconds to spare after an active shooter alert? Would teachers be held liable for their actions or decisions?

Would teachers get firearms similar to the military-style AR-15 weapons that have been used in many mass shootings, including in Parkland? What’s the risk of a troubled person attempting to disarm a teacher, and use his or her weapon? Who would pay for the billions of dollars it would take to pay for guns, ammunition and training, when so many schools currently lack nurses, guidance counselors, school resource officers and have a multitude of other needs?

These questions have alarmed many people — from the sheriff of Broward County in Florida, a teacher and former Marine in Pennsylvania, and numerous teachers, including responsible gun owners who participated in a telephone town hall hosted this week by the American Federation of Teachers.

Schools, airplanes, hospitals and federal court houses are gun-free zones. Why isn’t the president trying to keep schools this way? Why isn’t he taking common-sense steps to end this scourge? A possible reason: The National Rifle Association supports this idea and the gun manufacturers supported by the NRA would make a heck of a lot of money.

Americans are rightly frightened, outraged and frustrated by school shootings and the unnecessary loss of life. The NRA wants Americans to believe that only more guns can prevent tragedies. That is just not the case. Since Australia changed its gun laws in 1996, it has had no more mass shootings, while there have been scores in the United States. We know how to reduce gun deaths, but who will lead the effort?

If leaders want our schools to be armed, arm them with adequate resources: counselors, school nurses and reasonable class sizes.

Make our schools sanctuaries, not fortresses.

Randi Weingarten is president of the American Federation of Teachers.