A monstrous in-school cop, Joshua Carrier, received 70 years to life Friday for the sexual assaults of 18 Horace Mann Middle School boys. It’s an appropriate sentence that removes a menace from our community.

The Carrier case, though more dramatic than most, is nothing isolated or unusual. Rapists are having their way with children in public schools, throughout the country, at an alarming rate.

Here’s how The Associated Press put it, back in 2007, after a yearlong national investigation that was all-but ignored by the rest of the nation’s media.

“Students in America’s schools are groped. They’re raped. They’re pursued, seduced and think they’re in love,” said an introductory story to the AP’s three-part series, which was supported by irrefutable data and evidence.

“An Associated Press investigation found more than 2,500 cases over five years in which educators were punished for actions from bizarre to sadistic.

“There are 3 million public school teachers nationwide, most devoted to their work. Yet the number of abusive educators — nearly three for every school day — speaks to a much larger problem in a system that is stacked against victims.

“Most of the abuse never gets reported. Those cases reported often end with no action. Cases investigated sometimes can’t be proven, and many abusers have several victims.

“And no one — not the schools, not the courts, not the state or federal governments — has found a surefire way to keep molesting teachers out of classrooms.”

That and other stories in the series went on to explain how known abusers are often passed from one school to the next, with colleagues turning a blind eye.

The AP report came after a 2004 congressional report told us much the same. Federally sanctioned researchers reviewed 225 sexual abuse complaints made against teachers over a four-year period.

“None of the abusers was reported to the authorities, and only 1 percent lost their license to teach,” the federal report stated. “Only 35 percent suffered negative consequences of any kind, and 39 percent chose to leave their school district, most with positive recommendations. Some were even given an early retirement package.”

Society’s reaction to this and other alarming findings of the AP and congressional reports? A palpable “who cares?” No one did a thing. Congress did not establish a protocol that might protect children. The secretary of education was not asked to hold a summit and figure out a strategy for child protection. Nothing.

In 2010, the crisis came on our radar again when the Denver Post — much to the publication’s credit — weighed in. Eight Front Range teachers had been arrested and charged with abusing school children in just six months, and the Post told the story of a 15-year-old Colorado Springs girl who was groomed and molested by a track coach twice her age. The Post reported that one in 14 girls in grades 5 to 8 were known to be sexually abused, based on numbers from the Rape and Incest Network. For high school girls, the number was 1 in 9. For boys, such as the victims of Carrier, the abuse rate was roughly half.

The Catholic church had a crisis with childhood sexual abuse, but it was nothing approaching the magnitude of what’s going on in public schools. And the church, to its credit, held a United States summit in 2002 that resulted in a massive new Washington bureaucracy charged with protecting kids and eradicating sexual abuse from Catholic institutions. This isn’t to forgive problems in the church, not in the least. The church has paid, will continue to pay and the abuse cannot be explained away. It’s only to point out that one major institution has, at least, taken steps to protect children going forward.

We may see more studies emerge, telling us the horrific size and scope of the sexual abuse crisis in public schools. But we don’t even need them. Anyone who reads a newspaper or watches the evening news knows that abuse in our schools has become far too common. It’s no longer shocking to hear of a teacher up on charges for having sex with one or more students.

Institutions and governments cannot possibly prevent all crimes. But they can reduce crime. It’s time for Congress, the Department of Education, the media and local school boards to stop acting as if these rapes of children are isolated events. They are not. It is time for a coordinated, institutional effort to protect our kids from criminals, like Joshua Carrier, who infiltrate our schools.