“We'll reinforce along priority points of entry so as to enhance [Border Patrol]’s ability to harden and secure the border,” Air Force Gen. Terrence O’Shaughnessy, head of U.S. Northern Command said at a news conference in Washington, D.C., adding that the deployment would be completed by the "end of this week."
The reinforcements headed to the U.S.-Mexico border are support troops – not combat troops – and will include three engineering battalions with "heavy equipment", as well as aviation and medical personnel. Most of the troops are on active duty and will carry weapons, but will not be part of any law enforcement effort in deference to the Posse Comitatus Act, which prohibits the federal government from using the armed forces in a domestic police role.
The troop deployment, first reported by The Wall Street Journal, had been expected after Defense Secretary Jim Mattis approved the request last week. But the number of troops is far higher than initial estimates.
There are three planned staging areas: in South Texas, Arizona and California, for what's now been dubbed Operation Faithful Patriot. The mission's U.S. ground commander is Army Lt. Gen. Jeffrey S. Buchanan, who was sent to Puerto Rico last year to lead Hurricane Maria relief efforts.