A disturbing series of incidents on the southern border demonstrate what’s at stake when our leaders refuse to take illegal immigration seriously. Juan Carlos Perez-Medina was apprehended on Nov. 13, and he had with him entry-rejection paperwork from more than two years ago. Two ICE agents were analyzing the situation when Perez-Medina assaulted one of them and then jumped a delineator known as the “limit line,” cutting off the agents’ access to him.

The story doesn’t end there, however. Not 24 hours later, Perez-Medina attempted another illegal entry. And just like the previous day, agents apprehended him. Peculiarly, though, no charges were handed down for the assault he had just committed. So instead of going to jail and facing trial, he was intentionally shipped back to Mexico. What could go wrong?

Well, the story still doesn’t end there. On Nov. 17, Perez-Medina, apparently believing the third time’s a charm, set into motion yet another illegal entry. He moved toward and antagonized agents, reportedly even ominously bellowing, “I’m going to come back and kill you.” He then punched an agent before teammates interfered and cuffed Perez-Medina. This time, he was finally handed a serious charge: felony assault on a federal officer. Better late than never?

The strangeness and questionable decisions of this case notwithstanding, it’s good learning material. In Harford County, located on the outskirts of Baltimore, Maryland, “More than 40 people facing possible deportation were flagged by deputies as they came into the county jail,” CBS Baltimore reports. “Harford county correctional deputies are not only scanning arrestees’ criminal backgrounds, but also their immigration status.”

Four of the deportation candidates are associates of MS-13. And if you’re curious as to what MS-13 is capable of, the New York Daily News recently reported, “Authorities have arrested a 19-year-old member of the MS-13 gang in connection with the stabbing death of an unidentified man whose decapitated body was found with the heart removed.”

These people should be taken seriously, and good for Harford County for realizing it. Sheriff Jeffrey Gahler is right: “These are offenders who are not only here in the country illegally, but have committed acts that the federal government feels that they shouldn’t be returned to our community.” But that’s difficult to do when there’s a lack of binding policies. On the one hand, Hartford County is being proactive and seeking to deport dangerous men. But that’s undermined when other dangerous guys like Perez-Medina are given second chances and they can simply re-enter (hence the need for a border wall and unsparing prosecution). That’s one way MS-13 gets here in the first place. Unified enforcement and prevention are the key to a healthy and strong immigration system.