For decades, Ronald Reagan's Strategic Defense Initiative (SDI)—an ambitious ground- and space-based "shield" to protect the United States from nuclear ballistic missiles—has been mocked and criticized. First proposed by the president in 1983, it was immediately dubbed "Star Wars" by the mainstream media and dismissed as unscientific, infeasible and even counter-productive. The Union of Concerned Scientists, 100,000 members strong, was fierce in its opposition. The Arms Control Association declared that SDI would end arms control, while some Soviets felt SDI would end the world. Domestic critics became furious, and the Kremlin went ballistic.

But while Reagan's critics might not have taken his pet technology seriously, the Russians certainly did. Even though SDI was decades away from being implemented, if not beyond the reach of technology altogether, the threat the shield presented—along with Reagan's dogged commitment to it—was enough to scare Soviet leader Mikhael Gorbachev into reforms that would eventually bring down the Soviet Union. In short: "Star Wars" never worked as Reagan wished. It worked even better. And I should know, because I saw it happen.


It all began in October 1986, when the two cold-warring powers convened in Reykjavik, Iceland, to discuss the agenda for the "real summit" scheduled for December. To me, accompanying the delegation as U.S. director of arms control, the weekend in Reykjavik felt less like a typical superpower summit than it did an Agatha Christie thriller: The two principal characters—Reagan and Gorbachev—were vivid; the plot was full of cliffhangers; and the setting—a creaky old house, desolate, reputedly haunted, rain lashing against its windowpanes—ominous.

First on the agenda was weapons control, and Gorbachev arrived prepared to discuss SDI. He realized—and he said this during the negotiations—that if deployed as Reagan wished, SDI would be the end of "mutually assured destruction," the strategic concept that kept the nuclear standoff manageable. And not only would it negate, or at least diminish, the power of the Soviet Union's land-based ballistic missiles, but it would also pierce the aura of awesome Soviet might that accompanied them. Apart from that aura of power, the Soviet Union didn't have much going for it—surely not any economic vibrancy or political attractiveness.

At the time, the Soviets lacked the technological infrastructure and resources to compete with such a sophisticated missile defense system. As Gorbachev told the Politburo in his pre-Reykjavik preparation sessions, their country was maxed out on defense spending.

A decade before Gorbachev came to power, I witnessed a "barroom brawl" between my boss, then-Secretary of Defense (for the first time) Don Rumsfeld, and then-CIA Director George H. W. Bush. The two squared off over whether the Soviets were allocating 9 to 11 percent (Bush's view) or 11 to 13 percent (Rumsfeld's view) of their GDP for defense. Both estimates seemed relatively high: At the time, the United States was spending roughly 5 percent.

During a brief opening of Kremlin archives in the mid-1990s after the fall of the Soviet Union, it was discovered that the number was actually between 30 and 40 percent—and had been for several decades. This was a staggering figure, as Gorbachev well knew. The Soviet government simply could spend no more. (By comparison, at the height of the World War II life-or-death struggle for civilization, the hottest of all wars, U.S. defense spending had topped off at 35 percent of GNP, where it stayed for just one year.)

Gorbachev had known about SDI before the summit, and, as his conversations with the Politburo in preparation for the summit reveal, he was wary of it. But going into the October meeting, he was confident he could offer Reagan a deal the president couldn't refuse—dramatic nuclear weapons cuts (both strategic and intermediate-range) in exchange for Reagan's killing off SDI.

Gorbachev made this offer at Reykjavik, dangling the arms reductions and even proposing to eliminate the entire Soviet nuclear arsenal within the next ten years—huge concessions at the time—all before explaining at the last minute that this hinged on Reagan's putting the brakes on SDI development.

Ken Adelman, author of Reagan at Reykjavik: Forty-Eight Hours that Ended the Cold War by Broadside Books, an imprint of HarperCollins, was U.S. arms control director during the October 1986 summit in Iceland and a U.S. ambassador to the United Nations before then.