Von Hippel replies: As Alex DeVolpi states, many more physicists than I could mention worked in the US and Europe to try to unwind the extraordinarily dangerous nuclear confrontation created by the Cold War. And the task sometimes required considerable courage. The McCarthy period in the 1950s was notable in that connection. For those interested in learning more about that period, I recommend Jessica Wang’s book American Science in an Age of Anxiety: Scientists, Anticommunism, and the Cold War (University of North Carolina Press, 1999), which is based in part on 23 partially declassified volumes of files from the Federal Bureau of Investigation’s probes of the Federation of American Scientists. For a good overview of the history of the global anti–nuclear weapons movement, see Lawrence Wittner’s book, Confronting the Bomb (Stanford University Press, 2009).

James Benford is correct that the Soviet Union had a major program in ballistic missile defense. However, although the Reagan administration’s Department of Defense refused to believe it, the program had pretty much ended by the time we visited the Sary Shagan ballistic missile defense R&D test site in 1989. A number of histories have been written about the program and Mikhail Gorbachev’s role in ending it with advice from Evgeny Velikhov. One of those histories, in the book The Dead Hand: The Untold Story of the Cold War Arms Race and Its Dangerous Legacy (Doubleday, 2009), by former Washington Post Moscow bureau chief David Hoffman, is based in part on Soviet Central Committee files. According to Hoffman, the 1987 Polyus launch did not contain an actual laser but rather a mockup, and the effort to put the mockup into orbit failed. That apparently was the end of the Soviet program on space-based lasers.

Gregory Benford (James’s brother) argues that the Reagan administration’s Strategic Defense Initiative (SDI) was intended to help entice the Soviets to reach the arms-control agreements that were part of the unwinding of the Cold War. That is a popular part of the Reagan hagiography. As described in my article, however, Velikhov and his colleagues persuaded Gorbachev that if the technologies such as space-based lasers proposed by the SDI program were ever deployed, they could easily be neutralized with much less costly countermeasures.

Andrei Sakharov predicted in 1987 that SDI would collapse under its own weight, and it quickly did, in significant part due to the withering criticism of independent US physicists such as Richard Garwin. Also, the argument that it took SDI to bring the Soviets to the bargaining table is exactly backward. It was the national security officials in the early Reagan administration who delayed negotiations for two years after reformers came to power in the Soviet Union. An authoritative account of the battles over nuclear arms control inside the Reagan administration can be found in a series of books by Strobe Talbott. See especially the final book, The Master of the Game: Paul Nitze and the Nuclear Peace (Vintage Books, 1988).

With regard to John Swegle’s comments, the arguments about SDI and the end of the Cold War have been dealt with above. On some of his other points I offer the following remarks.

Swegle is correct that US deployment of ground-based cruise and intermediate-range ballistic missiles to Western Europe was justified by Soviet modernization of its intermediate-range ballistic missiles targeted on the region. He also is correct that although few in the Reagan administration imagined that the Soviets would accept the “zero option,” those missiles did give the US the bargaining chips that made possible the 1987 bilateral treaty eliminating intermediate- and medium-range missiles.

The US 10-warhead MX intercontinental ballistic missile was put forward not as a bargaining chip but for attacking Soviet missile silos. The connection to the Soviet 10-warhead SS-18 was the fear that it could be used to attack US missile silos. We now know from Central Committee records that the SS-18 was not accurate enough to do so.1 

Swegle is also correct that the final determination as to whether or not a shallow explosion-like event was a nuclear test requires onsite inspection. But it is necessary to detect and locate the event first. Gorbachev’s agreement in 1986 to allow a foreign organization to install seismometers around the Semipalatinsk test site set the stage for today’s international detection system managed by the Comprehensive Nuclear-Test-Ban Treaty Organization in Vienna.

It is generally accepted that Russia under Boris Yeltsin did eliminate virtually all of its army’s tactical nuclear weapons and withdrew from deployment other classes of nonstrategic nuclear weapons as committed by Gorbachev in October 1991. There were no verification arrangements, however, so there continue to be questions about the complete implementation of the warhead destruction part of the commitments.

Finally, James Carroll is, of course, correct: Germanium radiation detectors are semiconductors, not scintillators.

“The Window of Vulnerability That Wasn’t: Soviet Military Buildup in the 1970s”
), http://russianforces.org/podvig/2008/06/the_window_of_vulnerability_that_wasnt.shtml.