A Pentagon memo signed by Defense Secretary James Mattis and released Friday night approves up to 4,000 National Guard members for a "southern border security mission while under the command and control of their respective governors" through the end of September.
To start the deployment, Arizona will send 150 National Guard members to police the southern border beginning next week, the state government announced Friday, and Texas will send 250. "We appreciate the governors' support and are dedicated to working with them to secure the national borders," said a statement from Mattis and Homeland Security Secretary Kirstjen Nielsen.
This is not the first time recent presidents have sent troops to do border patrol; President George W. Bush deployed 6,000 National Guard forces in 2006, and President Obama sent 1,200 in 2010, both claiming the same legal authority, Title 32, which President Trump cites now. Trump has said he wants border security to be a military matter because "our Military is again rich," while his border wall expansion plan is still not fully funded by Mexico or the GOP-majority Congress.