Strategic Defense Initiative
The Strategic Defense Initiative or SDI, which is also commonly called Star Wars[Citation Needed], was a proposal by U.S. President Ronald Reagan in 1983 to build a ground based and space based system to protect the U.S. from nuclear ballistic missiles. The system was never fully set up, but the research from this paved the way for the anti-ballistic missile systems of today[Citation Needed].
Goals of SDI
The basic goal of SDI was to intercept and destroy incoming nuclear ballistic missiles to prevent detonation over the U.S. In some scenarios, not all warheads would be intercepted, but enough would be to render [[[Mutually Assured Destruction|mutually assured destruction]] moot. In the scenario of "partial protection", the U.S. would be immune from complete destruction, which would deter the USSR from launching a first strike. See Game theory and Mutually Assured Destruction.