During Reagan's presidency, what initiative was introduced to enhance missile defense?

The Strategic Defense Initiative (SDI) was introduced during Reagan's presidency as a program aimed at enhancing missile defense. Announced in 1983, SDI proposed the development of a system that would use ground-based and space-based systems to defend against strategic nuclear missile attacks, primarily from the Soviet Union. The initiative reflected Reagan's emphasis on technological superiority and the belief that advanced defense systems could protect the United States and its allies from a nuclear threat. This program was characterized by its ambition to create a defensive shield rather than relying solely on deterrence through mutually assured destruction, which had dominated Cold War nuclear strategy.

The SDI was significant in the context of U.S.-Soviet relations during the 1980s, as it escalated tensions by suggesting an ability to defend against nuclear attacks, which some perceived as undermining the traditional nuclear balance of power. The strategic vision of the SDI had lasting implications for military policy and international relations, influencing subsequent arms control discussions and defense technology development.