GAO: How DOD funded southern border operations totaling $2.64B in obligations

On July 13, 2026, the U.S. Government Accountability Office (GAO) released a federal watchdog report on how the Department of Defense (DOD) funded its support for southern border operations, starting with a DOD funding shift that began in fiscal year 2025.

GAO reports that, as of March 31, 2026, DOD had reported $2.64 billion in obligated costs for those operations and that the department used multiple funding strategies plus a cost-tracking process.

For taxpayers and Congress, the key term is “obligated costs.” GAO frames obligations as commitments that create a legal liability for payment for goods or services ordered or received—so the figure reflects what the government had committed by the reporting date, not necessarily what had already been fully disbursed.

$2.64 billion in obligated costs — plus $305 million eligible for DHS reimbursement

GAO says DOD’s $2.64 billion in obligated costs (as of March 31, 2026) covers both DOD-directed activities—such as securing DOD-administered lands along the border (known as National Defense Areas) and constructing permanent border barriers—and DOD support to the Department of Homeland Security (DHS) in response to assistance requests.

GAO further reports that, of the $2.64 billion obligated, DOD reported $305 million is eligible for reimbursement by DHS.

GAO also notes that DOD’s cost reporting changed starting in fiscal year 2026 to account for reimbursable support, which is one reason readers should treat the $305 million figure as a reimbursement eligibility classification within the reporting totals—not an additional, separate spending bucket.

How DOD funded it: multiple money streams beginning in FY 2025

GAO says DOD used multiple strategies to fund southern border support beginning at the start of fiscal year 2025 and continuing into fiscal year 2026. The report highlights these funding moves:

• Realigning $1.74 billion in funding appropriated for fiscal year 2025 from various funding categories.
• Transferring $608 million from or through DOD’s Drug Interdiction and Counter-Drug Activities, Defense account.
• Relying on $300 million from within existing military construction appropriation accounts for border barrier projects.
• Beginning to obligate $1 billion appropriated in Public Law 119-21 (commonly known as the One Big Beautiful Bill Act).
• Providing some DHS support in FY 2026 that is eligible for reimbursement.

How GAO says DOD tracked costs: Advana as the “authoritative” system

GAO’s focus is not only on the totals, but on whether costs can be traced and reported reliably. The report says the Office of the Under Secretary of Defense (Comptroller) and the military services established a tracking process that included guidance and “business rules” for pulling data from services’ financial ledgers into Advancing Analytics (Advana), DOD’s enterprise-level management system used for reporting.

GAO also describes an April 25, 2025 Comptroller memorandum saying Advana would be the authoritative and only source for reporting on the use of funds for border operations. GAO reports that DOD components provided business rules allowing Advana to pull transaction details from component systems, along with validation steps for accuracy and completeness.

GAO adds a caution: it says it could not ascertain the complete reliability of Advana or the systems feeding it, but GAO believes the cost-summary reports based on Advana provide acceptable approximations of obligations at the time of GAO’s analysis.

What to watch next: audit work and a possible legal decision

GAO says the next accountability steps include:

• An audit by the Army Audit Agency to determine whether the Army accurately recorded and reported costs for southern border operations and whether it was fully and accurately reimbursed for eligible costs. GAO says the audit is expected to be complete by the end of calendar year 2026.
• A legal decision later in 2026 GAO expects to issue (based on a congressional request) on whether DOD complied with statutory requirements when it obligated military construction funds for a border barrier at the Barry M. Goldwater Range.

Bottom line: GAO’s headline number—$2.64 billion in obligations as of March 31, 2026—depends on how DOD categorizes, extracts, and reports those costs over time. The audit and any follow-on legal review are what readers should watch to see whether the obligations totals remain fully traceable as reporting continues.

Sources

• U.S. GAO report page: Southern Border Security—DOD Used Multiple Strategies to Fund Operations (GAO-26-108437)
• GAO-26-108437 full report (HTML)