Trump has sent thousands of troops to the Mexico border

Oliver O'Connell

On the 2024 campaign trail, Donald Trump pledged to deploy thousands of troops to secure the southern border of the US as part of his strategy to clamp down on illegal immigration. The president's characterisation of the situation at the US-Mexico border as an "invasion" had already been met with criticism, which grew with the idea of the domestic deployment of the military. Democrats, human rights groups, and even some groups within the military itself raised their concerns. Nevertheless, after his inauguration, troops were deployed to the border within a week, with more following along with U-2 spy planes, Stryker combat vehicles, drones, helicopters, and even two Navy destroyers off the west coast and in the waters of the Gulf of Mexico off Texas. Approximately 8,600 active duty troops are now at the US-Mexico border, up from about 2,500 at the end of the Biden administration.

Border crossings had fallen sharply in the latter part of Joe Biden's presidency but plunged as Trump took office. Some 8,000 people were arrested after crossing the border illegally this April, the most recent data shows. The corresponding figure for a year earlier in April 2024 was 128,000.

In the vernacular of the Trump administration: "Promises made, promises kept." But what exactly are the troops at the border doing, and is their presence the key factor in the reduction of border crossings? Furthermore, how much does this cost, and what is the overall impact on military readiness? Should they be doing something else somewhere else? To date, this has all cost around $525 million, according to a figure from the Department of Defense reported in The New York Times. While the deployments continue to grow, so does the military's authority over territory along the border. The Pentagon has created two narrow strips of land, effectively turning them into parts of nearby US military bases as a buffer zone with Mexico.

They are overseen by Army commands at Fort Bliss, near El Paso, Texas, and Fort Huachuca in Arizona. Any migrants entering these areas are considered to be trespassing on military land and can be temporarily detained by US troops until Border Patrol agents arrive. However, this has faced some legal challenges regarding whether migrants are aware they are trespassing in a restricted area, and there is skepticism about whether many such incidents will occur. Critics also argue Trump is carrying out an end run around the longstanding Posse Comitatus Act, which generally bars the military from domestic law enforcement. More than anything, the military's presence seems to provide a deterrent effect to people smugglers and cartels, and the troops won't be going anywhere anytime soon. The border mission is expected to last for years to address cyclical and seasonal increases in migration, Gen. Gregory Guillot, the head of the military's Northern Command, told Congress.

On a day-to-day basis, troops support local law enforcement agencies, patrolling on foot, by helicopter, and in combat vehicles in a highly visible surveillance capacity that also underlines their deterrence capabilities. The Stryker combat vehicles being used are 25 tons, seat 11, and have eight wheels, reaching speeds of 60 mph. They are often positioned on a strategic overlook where smugglers and cartel members can see them, and vice versa, as they have optical sights that can spot individuals or groups up to six miles away. To answer the question of what they would otherwise be doing if not deployed at the border, the Times notes that a Stryker battalion in Texas was scheduled for training at Fort Irwin in California and would then deploy to South Korea. Those assignments have been postponed. Other battalions would similarly be training for deployment in Eastern Europe, the Middle East, or other parts of the Indo-Pacific arena.

On Capitol Hill, this has raised questions as to whether this is the best use of the military. Senator Jack Reed of Rhode Island has been particularly vocal in his opposition. As the top Democrat on the Armed Services Committee, he said on May 8: "It is difficult to explain the border missions as anything but a distraction from readiness."