There’s a community college in Texas that’s offering lessons about border security amid the heated national debate about President Trump’s proposed wall along the U.S.-Mexico border, but it’s not for credit and students won’t find it in the course schedule.

All they have to do is take a look along the southern boundary of the Laredo Community College campus, which is one of the only places in the area protected by a wall. Matt Pinsker, a national security expert and professor at Virginia Commonwealth University, described his time riding along with Border Patrol as a new prosecutor, and how the eight-foot-tall steel “fence” transformed what was previously a prime crossing and drug trafficking point into a safe haven for students.

In a column for the National Review, Pinkster explained that “college administrators were inundated with phone calls about illegal aliens cutting across its campus. Though most aliens were nonviolent and left the students alone, not all of them did. There were thefts, assaults, robberies, and more.”

He continued:

Border Patrol agents were constantly receiving emergency calls about the mayhem on the campus – and of course, when agents showed up, the aliens would take flight, creating dangerous and disruptive chases. Can you image if your school work workplace were the site of quasi-daily law enforcement hot pursuits? That was simply part of the Laredo Community College experience.

And although illegal immigrants were a nuisance, the real danger to the university and its students were the cartel members using the campus, specifically the tennis courts and parking lot, to make major drug deals. Right across the border from Laredo is the Mexican city of Nuevo Laredo. Like many border towns in Mexico, it has been completely taken over by the drug cartels.

The steel fence was completed in 2005 by military engineers and connects the south and north ends of the school’s 200-acre campus. Stone walls enclose the rest of the campus. The fence is topped with spike bars that curve toward Mexico, and it sits just yards from a calm stretch of the Rio Grande River.

Former college president Ramon H. Dovalina discussed the problems with drug smugglers and illegal immigrants crossing through the campus with the Valley Morning Star in 2007, and he said the fence drastically reduced the illegal activity at the school.

According to the Star:

 … Because of the college’s proximity to the river “there have always been a lot of crossers,” he said. But now the fence slows them down so Border Patrol can locate them, or it forces crossers to each end of the fence, he said.

Before the fence he would see migrants crossing through campus at least once a week, some in groups of two to three and some in bunches as many as 12 to 13, he said. After the fence was erected he’s only seen a woman with a baby, who was stopped by the fence and caught by Border Patrol, he said.

By forcing crossers to go around the fence, it also freed Border Patrol agents who previously patrolled the entire stretch to simply focus on the ends, or “choke points,” which saved manpower. Much like the current wall debate, those who initially criticized the structure made some of the same arguments in play now, including claims immigrants will just climb over or dig under the structure. Pinkster confirmed that some tried, but the extra effort gives Border Patrol additional time to respond, resulting in more arrests and better security.

“A fence isn’t a magical fix or cure-all,” Pinkster wrote. “It is a tool that, like any other tool, must be used properly and under the right circumstances to make a difference. It’s just common sense. To argue otherwise is to be willfully ignorant.

“But you know who isn’t ignorant about border security?” he concluded. “The graduates of the Laredo Community College. They learned all about border security in college.”