Missile Defense Agency MDA

President Reagan's Strategic Defense Initiative of 1983, nicknamed Star Wars, led to the creation of the Strategic Defense Initiative Organization in 1984. It became the Ballistic Missile Defense Organization in 1993 and the Missile Defense Agency in 2002, after the United States withdrew from the 1972 Anti-Ballistic Missile Treaty with Russia, which had limited such defenses. The agency develops and tests missile defense systems, then hands them to the military services to operate.

Its programs include the Ground-Based Midcourse Defense system, with interceptors in Alaska and California designed to stop a limited long-range missile attack on the United States, the ship-based Aegis Ballistic Missile Defense system, the Terminal High Altitude Area Defense system, and the sensors and satellites that track missiles in flight. It is headquartered at Fort Belvoir, Virginia, with major operations at Redstone Arsenal in Alabama and Schriever Space Force Base in Colorado.

Missile defense has long been debated over cost, technical reliability, and its effect on nuclear stability, since adversaries may respond by building more or faster missiles. In January 2025 the President ordered a much larger national missile defense effort, later named Golden Dome, including space-based interceptors to defend against ballistic, hypersonic, and cruise missiles. Supporters argued it was needed against new threats from China and Russia, while critics questioned its feasibility and its estimated cost of hundreds of billions of dollars.