Of course, this isn’t 1916 and the U.S. military certainly shouldn’t (and wouldn’t) unilaterally march into Mexico to impose law and order. But the Hernández v. Mesa case demonstrates just one of the problems with trying to police a highly porous border using conventional tactics. The ongoing drug wars, corruption, seemingly intractable human trafficking industry, and the growing number of families and unaccompanied minors fleeing Central America to enter at border checkpoints are all problems that Trump’s proposed solutions—a border wall and mass deportations—simply aren’t going to solve.

The cartels won’t be deterred by a wall, but they might be deterred by U.S. forces on their side of the border. Trump reportedly mentioned the possible deployment of American troops to Mexico in a phone call with Mexican President Enrique Peña Nieto earlier this month. But of course troops alone wouldn’t be enough. The U.S. would have to get serious about investing in Mexico’s long-term stability. That means more trade, not less, and better coordination with Mexico’s military and law enforcement agencies. After all, a stable and secure Mexico is in America’s best interest.

But all of this will require better U.S.-Mexico relations, which at the moment appear to be tanking. Secretary of State Rex Tillerson and Homeland Security Secretary John Kelly arrived in Mexico Wednesday to meet with Peña Nieto in hopes of soothing tensions over Trump’s executive order on deportations. That’s a good first step, but it should never have been necessary—and Trump himself will need to do more to repair the damage he’s already done.