On March 23, 1983 in a televised address to the nation, U.S. President Ronald Reagan announced his intention to embark upon groundbreaking research into a national defense system that could make nuclear weapons obsolete. The research took a number of forms which collectively were called the Strategic Defense Initiative, or SDI. 
Logo of the Strategic Defense Initiative Program
The heart of the SDI program was a plan to develop a space-based missile defense program that could protect the country from a large-scale nuclear attack. The proposal involved many layers of technology that would enable the United States to identify and destroy automatically a large number of incoming ballistic missiles as they were launched, as they flew, and as they approached their targets. The idea was dependent on futuristic technology, including space-based laser systems that had not yet been developed, although the idea had been portrayed as real in science fiction. As a result, critics of the proposal nicknamed SDI "Star Wars" after the movie of the same name.
There were several reasons why the Reagan Administration was interested in pursuing the technology in the early 1980s. One was to silence domestic critics concerned about the level of defense spending. Reagan described the SDI system as a way to eliminate the threat of nuclear attack; once the system was developed, its existence would benefit everyone. In this way, it could also be portrayed as a peace initiative that warranted the sacrifice of funds from other programs. Privately, Reagan was quite adamant that the goal of U.S. defense research should be to eliminate the need for nuclear weapons, which he thought were fundamentally immoral. In terms of the Cold War conflict with the Soviets, a successful defense system would destroy the Soviet ability to make a first strike, which in turn would undermine the USSR's ability to pose a threat to the United States at all. So success in this area, supporters of SDI argued, could potentially also bring an end to the Cold War.
Criticism of the SDI initiative was widespread, however, and it took several forms beyond general skepticism about the feasibility of the technology. First, research and development for such a complicated project inevitably came with a very high price tag. Many critics of SDI wondered why the Reagan Administration was willing to spend so much money on a defense system that might never work, and expressed alarm that the funding for SDI came at the cost of social programs like education and health care. Moreover, there was no way to test such a system without exposing the world to a very dangerous attack. Second, the very idea of guarding against nuclear attack struck at the heart of the theory of deterrence. If one nuclear power no longer had to fear nuclear attack, then there would be no fear of retaliation to stop it from making the first strike against another. In fact, if the Soviet Union thought that the United States was on the verge of deploying a comprehensive defense system, some argued, it might feel forced to attack before the United States could complete the system; this possibility meant that developing the system could actually contribute to U.S. insecurity, not the other way around. Third, critics both in the United States and around the world called the SDI initiative a clear violation of the 1972 Antiballistic Missile Treaty. That treaty had committed the United States and the Soviet Union to refrain from developing missile defense systems in order to prevent a new and costly arms race. The Strategic Defense Initiative appeared to be a missile defense system by another name.
The Soviet Union expressed its concerns about SDI almost as soon as it learned of it, and the prospect of the United States developing the defense system thus became a hindrance in the pursuit of future arms negotiations between the two powers. Soviet leader Mikhail Gorbachev linked his demands that the United States drop SDI to the negotiations for the Intermediate-range Nuclear Forces Treaty (INF Treaty) and the Strategic Arms Reductions Talks (START). Over the course of the 1980s, Reagan's refusal to give up SDI became the sticking point that prevented the two countries from reaching a deal on other arms control measures, and it was only when the two sides agreed to delink defense and intermediate-range forces discussions that they managed to sign the INF Treaty. START was completed after Reagan left office, and government commitment to the SDI project waned.
Logo of the Strategic Defense Initiative Program There were several reasons why the Reagan Administration was interested in pursuing the technology in the early 1980s. One was to silence domestic critics concerned about the level of defense spending. Reagan described the SDI system as a way to eliminate the threat of nuclear attack; once the system was developed, its existence would benefit everyone. In this way, it could also be portrayed as a peace initiative that warranted the sacrifice of funds from other programs. Privately, Reagan was quite adamant that the goal of U.S. defense research should be to eliminate the need for nuclear weapons, which he thought were fundamentally immoral. In terms of the Cold War conflict with the Soviets, a successful defense system would destroy the Soviet ability to make a first strike, which in turn would undermine the USSR's ability to pose a threat to the United States at all. So success in this area, supporters of SDI argued, could potentially also bring an end to the Cold War.
Criticism of the SDI initiative was widespread, however, and it took several forms beyond general skepticism about the feasibility of the technology. First, research and development for such a complicated project inevitably came with a very high price tag. Many critics of SDI wondered why the Reagan Administration was willing to spend so much money on a defense system that might never work, and expressed alarm that the funding for SDI came at the cost of social programs like education and health care. Moreover, there was no way to test such a system without exposing the world to a very dangerous attack. Second, the very idea of guarding against nuclear attack struck at the heart of the theory of deterrence. If one nuclear power no longer had to fear nuclear attack, then there would be no fear of retaliation to stop it from making the first strike against another. In fact, if the Soviet Union thought that the United States was on the verge of deploying a comprehensive defense system, some argued, it might feel forced to attack before the United States could complete the system; this possibility meant that developing the system could actually contribute to U.S. insecurity, not the other way around. Third, critics both in the United States and around the world called the SDI initiative a clear violation of the 1972 Antiballistic Missile Treaty. That treaty had committed the United States and the Soviet Union to refrain from developing missile defense systems in order to prevent a new and costly arms race. The Strategic Defense Initiative appeared to be a missile defense system by another name.
The Soviet Union expressed its concerns about SDI almost as soon as it learned of it, and the prospect of the United States developing the defense system thus became a hindrance in the pursuit of future arms negotiations between the two powers. Soviet leader Mikhail Gorbachev linked his demands that the United States drop SDI to the negotiations for the Intermediate-range Nuclear Forces Treaty (INF Treaty) and the Strategic Arms Reductions Talks (START). Over the course of the 1980s, Reagan's refusal to give up SDI became the sticking point that prevented the two countries from reaching a deal on other arms control measures, and it was only when the two sides agreed to delink defense and intermediate-range forces discussions that they managed to sign the INF Treaty. START was completed after Reagan left office, and government commitment to the SDI project waned.
