The National Defense Authorization Act (NDAA) is an annual law passed by the United States Congress that outlines the budget and expenditures for the country's defense. It sets funding levels for the Department of Defense (DoD) and other national security programs, ensuring that military personnel are paid and that equipment and resources are available for national defense. The NDAA also includes provisions for military policies, such as personnel management, procurement processes, and research and development initiatives. It plays a crucial role in shaping the U.S. military's capabilities and readiness to respond to various threats and challenges both domestically and internationally.