Trump admin takes consequential step as military gets broader power to detain border intruders

WASHINGTON, DC: The Trump administration on Friday, August 14, handed the military additional power to detain migrants accused of trespassing in areas that the Department of Defense controls as crackdown efforts on the southern border have recently intensified.

The legal opinion was released by the Justice Department's Office of Legal Counsel and concerns large swaths of land near the US-Mexico border.

After returning to the Oval Office for a second term, Trump designated the US-Mexico border area as "National Defense Areas" as part of the crackdown on illegal immigrants entering the US territory from this route.

As per the Posse Comitatus Act, the military is prohibited from enforcing laws on domestic soil, but the zones have allowed soldiers to detain migrants accused of entering the national defense areas, which are closed to civilians.  

As per the new arrangement, the Justice Department would be able to prosecute those arrested in the zones for trespassing.

Justice Department explains how the new arrangement works

The Justice Department said military personnel can arrest people who leave the national defense areas before they can be caught and charged with trespassing.

"In sum, we conclude that the use of military personnel to arrest trespassers just outside of an NDA would not violate the [Posse Comitatus Act], given the express statutory authorization and the military-purpose of a commander's traditional protective power," Deputy Assistant Attorney General William Hyde said in his opinion.

Six national defense areas have been set up along the southern border by the Trump administration so far. These are in Arizona, California, New Mexico, and Texas. According to Friday's opinion, the military may designate additional zones in the future.

The Justice Department began charging people arrested in April 2025 and has charged hundreds more since then.

Most face misdemeanor charges for violating military security rules or entering military, naval, or Coast Guard property. They can also face separate charges related to crossing the border.

US-Mexico border remains Trump admin's top mission

The US-Mexico border has been the first priority since Trump assumed power for his second term, as the department had announced plans to ramp up US forces there.

Notably, the legal opinion by the Office of Legal Counsel is advisory only and does not set any legal precedent.

In addition to enlisting the military's help at the southern border, the Trump administration has virtually closed the asylum system for those entering the US illegally. The crackdown has resulted in a sharp reduction in illegal crossings.