Pentagon border mission nears 10,000 troops as readiness concerns grow

The Pentagon’s border mission has become a large, open-ended deployment, with about 8,500 military personnel attached to Joint Task Force-Southern Border and another 1,100 expected to push the total close to 10,000. The expansion has delivered tactical gains along the U.S.-Mexico border, but it has also intensified concerns that the armed forces are being pulled farther from core warfighting work.

Since Joint Task Force-Southern Border took control in March 2025, the mission has logged more than 3,500 patrols, including more than 150 joint patrols with Customs and Border Protection and the Mexican military. Officials have said the troops are supporting CBP through detection, monitoring, data entry, warehouse work and patrols, not direct law-enforcement activity. In 2026, U.S. Northern Command folded the effort under the operational name Operation Ardent Vanguard, a label that now covers efforts to counter unlawful mass migration, narcotics trafficking, human smuggling and trafficking, and other criminal activity.

The deployment has pushed cartels and smugglers into more remote terrain, but that shift carries its own cost. Analysts and lawmakers have warned that a sustained domestic mission can divert money, attention and manpower from training and readiness. The Government Accountability Office has said the Defense Department needs better analysis and reporting of cost and unit-level readiness impacts from southwest border operations, and it has also noted that the Pentagon and the Department of Homeland Security have not agreed on a common outcome for the support mission.

Costs have become a major part of the debate. One 2025 estimate put the operation at about $1 billion over eight months, a figure that has sharpened scrutiny in Congress over morale, readiness and the long-term use of active-duty forces at the border. The military role also extended beyond ground forces: in 2026, the USS Augusta completed six months of operations in support of Northern Command’s border mission.

The legal and policy questions are not new. The Congressional Research Service has said troops on the border generally may not directly participate in law enforcement, though support and reconnaissance roles have been used before. The last major precedent came with Operation Jump Start, launched in 2006 under President George W. Bush and lasting through July 2008. At its peak, as many as 6,000 National Guard members served at a time, and more than 30,000 Army and Air National Guard personnel from all 54 states, territories and the District of Columbia rotated through the mission. The National Guard said the deployment supported Border Patrol without a direct law-enforcement role, and apprehensions fell after the buildup.