The National Defense Authorization Act (NDAA) is a series of United States federal laws that annually specifies the budget, expenditures, and policies for the U.S. Department of Defense (DoD) and other defense-related activities, such as nuclear programs within the Department of Energy. The first NDAA was passed in 1961, and it has been renewed every year since, making it one of the most consistent pieces of U.S. legislation. Its purpose is to authorize the funding levels and set the policies under which money will be spent, serving as a "permission-to-spend" bill, distinct from the separate appropriations bills that actually provide the funds.
The NDAA works by establishing defense policies, setting military personnel strengths, and authorizing procurement of weapons and equipment. Key provisions often address geopolitical concerns, such as the Fiscal Year 2022 NDAA including Section 847, which requires the DoD to develop a plan to reduce reliance on supplies from China, Russia, Iran, and North Korea. The scope of the NDAA has broadened beyond traditional defense to include areas like cybersecurity, sanctions compliance, and anti-money laundering (AML) provisions, such as the Anti-Money Laundering Act of 2020 being signed into law as part of the FY2021 NDAA.
The NDAA connects to the U.S. Constitution's requirement for Congress to provide for the "common defense" and is closely related to the annual defense appropriations bills. Recently, the NDAA for Fiscal Year 2024 included a significant change in Section 1250A, which prohibits the President from withdrawing the U.S. from NATO without congressional approval, marking the first statute to explicitly ban unilateral withdrawal from a treaty. Another recent change in the FY2026 NDAA amended the Military Selective Service Act to automatically register men between the ages of 18 and 26 for the draft, shifting the responsibility from the individual to the Selective Service System.