With this week’s horrific school shooting in Broward County, Florida, the latest angst-ridden round of national hand-wringing in America over guns and gun violence has begun.

Paradoxically, while gun sales have increased dramatically over the past two decades, the level of gun violence overall has declined sharply.  Yet the incidence and lethality of mass shootings, including a growing number carried out in schools, is clearly on the rise.

It hardly matters that these brazen attacks and their bloody slaughter still constitute a relatively small share of gun violence overall.  Or that far more youngsters die every month in a big city like Chicago than perish in a “typical” school shooting in small rural towns like Littleton, Colorado or Newtown, Connecticut.

The idea that a heavily-armed male teenager can walk into a public school and in a matter of seconds destroy the lives of innocents — many of them his own classmates — strikes the public conscience as unbearably savage and incomprehensible – and seems to demand swift and decisive action.

But addressing the problem at its root is easier said than done.  Consider some of the most widely debated short-term options:

Ban military assault weapons.  Actually, it was tried before — in 1994, and largely failed.  The AR-15, which isn’t even the deadliest weapon a mass shooter could purchase and use, is everywhere these days.  While some say the weapon’s only purpose is to kill en masse, it’s also used for a variety of other purposes, from sport-shooting to hunting.  One could try to ban the high-octane ammo magazines that allow AR-15 shooters to spray a large number of bullets quickly.  It’s a sensible measure, but it won’t stop the shootings.

Impose stronger gun purchase restrictions.  Everyone seems to agree that those with demonstrated mental illness should be prevented from buying guns, and a higher age limit might make sense, too.  Nikolas Cruz was just 18 when he purchased his AR-15, which seems absurd.  Here again, though, it’s a limited restriction.  Most of the mass shooters have no such demonstrated mental condition, and some that do, like Adam Lanza, the author of the Newtown shooting, obtained all of his weapons from his mother’s gun cabinet.  Legal guns of many kinds are plentiful, and about half of the most recent mass shootings did not even involve assault weapons.

Strengthen school physical security.  Some schools are considering whether to add cameras and metal detectors at their entrance and to lock all school doors from the outside after classes begin.  These may seem like common sense measures but many schools oppose them because they are costly to implement, restrict mobility and breed negative PR.  “We don’t want to turn our schools into prisons” is a common refrain.  Many inner city schools already have these systems in place, but suburban and rural schools are often reluctant to follow suit.

Arm the teachers.  This is becoming an increasingly attractive option, with nine states allowing it, and a growing number of school districts moving forward.  In some cases, the teachers merely store their guns in a locker.  However, increasingly teachers are being allowed to carry their weapons right into the classroom.  The weapons aren’t holstered, but remain concealed under special clothing.  Students, as a rule, don’t actually know which of their teachers is armed on any given day.  School officials publicize their stance, usually posting flyers or placards at school entrances warning would-be attackers that the school is prepared to defend itself.