When Donald Trump brought up the multinational gang MS-13 in his State of the Union speech, critics accused him of either exaggerating or exploiting the threat in order to push his hard-line immigration policies. A lengthy feature from the Washington Post suggests otherwise. One high school in Brentwood narrowly avoided a sixth murder by MS-13 students in a year with the capture of a hit squad, and one of the murder victims told her mother right before getting killed that MS-13 was “taking over the school.”

And it’s not the only school to have been taken over:

The Dec. 6 arrests of Rivera and four others thwarted what police say would have been the sixth murder of a Brentwood High School student by MS-13 in less than two years.

But the incident also shook the school for another reason.

All but one of those arrested attended Brentwood, according to Suffolk County police. Three were unaccompanied minors who had been caught at the border and then placed in the community by a federal refugee program.

From New York to Virginia to Texas, schools in areas racked by MS-13 violence are now struggling with a sobering question. What to do when the gang isn’t just in your community, but in your classrooms?

For the past year, the Trump administration has waged a nationwide crackdown on MS-13. Nowhere has this effort been more intense than in Suffolk County, where police say the gang has committed 27 murders since a surge of unaccompanied minors began arriving in 2013.

Be sure to read the whole piece, a well-balanced feature that also includes immigration attorneys and civil-liberties groups claiming that the threat is overblown. However, the report from the Post’s Michael Miller paints a different picture overall, one in which a lack of attention has turned schools into battlegrounds.That’s not to say those gang problems didn’t exist prior to the arrival of MS-13. Brentwood’s infiltration by MS-13, for instance, has fueled a rise in gang violence from the Latin Kings and Bloods, who have responded with reprisals to their eclipse by MS-13.

The Latin Kings and Bloods are mainly US-based gangs, however. MS-13’s impact comes directly from immigration policies that allowed unaccompanied minors entering illegally to be released, especially during the surge in 2013. The Office of Refugee Resettlement placed these minors in places like Brentwood, Suffolk, and other areas of the US, but their screening somehow missed MS-13 infiltration. Now high schools and local police are getting overwhelmed by this violent and virulent gang to the point where students are going missing and teachers and administrators can do little to stop it.

The Trump administration has stepped up federal enforcement efforts, but they’re still playing catch-up. The Department of Justice’s Operation Matador arrested 220 suspected MS-13 gang members in Mineola, New York in January, not long before the State of the Union address, but that appears to be a small percentage of the problem in that area. Critics claim that the arrests, which involved Brentwood High students, was too overbroad:

Some parents and activists say some of those included in the tally are innocent teenagers who came to the U.S. as unaccompanied minors, spending weeks locked in maximum-security detention centers based on flimsy and false allegations of gang activity. Civil liberties lawyers say that in some cases their alleged “activity” was wearing a black T-shirt or making a hand gesture.

“They said we have a warrant for your arrest and we don’t have to explain anything to you now. We will tell you when you come with us,” one teenager, who asked not to be named because she is afraid of being deported, told the AP in Spanish. “Later, they told me I had been associated with gangs.”

The teenager said she was not a member of MS-13. She said she knew of people in MS-13, as do most people at Brentwood High School, a large high school 45 miles east of New York City. Maybe she’s talked with some of them in the hallway. …

Immigration attorney Dawn Guidone said she represented about seven teenagers detained on gang allegations, and at least two were deported. One student said all he did was wear blue to school, the color of the gang. Officials said he was associating with “known gang members.”

“But the gang member he was associating with sat next to him in math class,” Guidone said. “If that’s ‘associating,’ then I don’t know how to even deal with that.”

This is why prevention works better than round-ups. Prevention in the form of strong border barriers and immigration policies that rely on immediate returns rather than mass infiltration would not necessitate the kind of anti-gang enforcement measures that can get abused or misused in the manner described above. This is an excellent demonstration of why any attempt to normalize DACA has to be accompanied by measures which will remove the incentives for illegal border crossings, especially by unaccompanied minors.

This MS-13 threat could have largely been avoided had we fixed the border back in 2006 when Congress voted to authorize a wall, or if we had gotten serious about ending catch-and-release policies. It’s time to fix both problems.