This bill, known as the "Border Security is National Security Act," authorizes the appropriation of $10,000,000,000 to the Department of Defense (DoD) to provide military support for securing the borders of the United States. These funds are intended to supplement existing appropriations and will remain available until September 30, 2028, specifically for DoD border security support to the Department of Homeland Security. The authorized funds may be used for a wide range of activities, including military personnel costs , procurement and operation of surveillance systems , intelligence analysis, and the installation of fences, barriers, and patrol roads . Additionally, the bill covers military aviation costs, procurement of counter-UAS systems , ground vehicles, and training. It also grants the Secretary of Defense authority to transfer these appropriated amounts for military personnel, operations, maintenance, and procurement, subject to a 45-day notification to congressional defense committees.