Declaring the US was lagging the Soviet Union in the nuclear arms race, President Ronald Reagan launched the wildly ambitious Strategic Defense Initiative (SDI) to render Soviet ballistic missiles "impotent and obsolete." It was envisioned as a defensive global shield with thousands of land-, sea-, air-, and space-based sensors and interceptors that would destroy Russian missiles in flight — and it never happened.

Advocates have claimed that in the high-stakes poker game between the US and the USSR, Reagan — master of shaping public perception — used the expensive SDI to scare Moscow into folding and hastened its collapse. That's debatable.

Upon Reagan's death in 2004, Daryl Kimball, of the Arms Control Association, wrote an assessment of Reagan's legacy on nuclear weapons. That legacy is marked not only by the massive nuclear weapons buildup but the catalyzation of "widespread anti-nuclear activism that increased the political impetus for nuclear arms control" — which ultimately culminated in an accord with Russian President Mikhail Gorbachev on limits for both countries' arsenals.

2016 World Nuclear Forces

A look at the total number of nuclear warheads worldwide, the number of deployed warheads, and the countries that possess reactors, warheads, uranium mining or other atomic facilities.

SDI’s aims at the time were deemed technologically unfeasible, but it has facilitated advances in communications, sensors and computing technology—and it set the stage of current ballistic missile defense programs. Years later, the US and its allies have only smaller systems that provide some defense against a piecemeal ballistic-missile attack launched from an unsophisticated opponent, Robert Farley, of the Patterson School of Diplomacy and International Commerce, wrote in an assessment of SDI.

"The United States still lacks a missile defense capable of defeating a determined attack by a sophisticated adversary," Farley writes.

This article is part of a larger Defense News 30-year anniversary project, showcasing the people, programs and innovations from the last three decades that most shaped the global security arena. Go to defensenews.com/30th to see all of our coverage.