Defusing the Nuclear Threat

Martin E. Hellman
Professor Emeritus of Electrical Engineering
Stanford University

Especially in recent years, whenever perturbations on our nuclear weapons posture are proposed they are rejected as too risky. The underlying societal belief is often expressed as, “We haven’t had a world war in 63 years – a record run. Nuclear deterrence has kept the peace, so let’s not mess with success.”

But how risky is our current posture? Despite a literature search and consulting with experts on risk analysis, national security, and nuclear weapons, I was unable to find any studies that estimated the failure rate of nuclear deterrence. How can alternative strategies be rejected as too risky if the baseline risk is unknown?

I therefore did a preliminary analysis based on just one potential failure mechanism, and found an estimated range of 0.02% to 0.5% per year for the failure rate of deterrence resulting in a full-scale nuclear war. Because this analysis considered only one potential failure mechanism, its estimated range is only a lower bound on the failure rate. Even so, the risk is orders of magnitude greater than society is willing to tolerate in related areas with less severe consequences.

The catastrophic failure rate for a modern nuclear power plant is less than 0.0001% per year. Hence, my preliminary analysis indicates that you are at as much risk from a failure of nuclear deterrence as if at least 200 to 5,000 nuclear power plants were built surrounding your home. For details see the appendix of my paper “Risk Analysis of Nuclear Deterrence,” which appeared in the Spring 2008 issue of The Bent of Tau Beta Pi, the magazine of the national engineering honor society.

A related statement endorsed by the following individuals,

  • Prof. Kenneth Arrow, Stanford University, 1972 Nobel Laureate in Economics
  • Mr. D. James Bidzos, Chairman of the Board, VeriSign Inc.
  • Dr. Richard Garwin, IBM Fellow Emeritus, former member President’s Science Advisory Committee and Defense Science Board
  • Adm. Bobby R. Inman, USN (Ret.), University of Texas at Austin, former Director National Security Agency and Deputy Director CIA
  • Prof. William Kays, former Dean of Engineering, Stanford University
  • Prof. Donald Kennedy, President Emeritus of Stanford University, former head of FDA
  • Prof. Martin Perl, Stanford University, 1995 Nobel Laureate in Physics


We, the undersigned, therefore urgently petition the international scientific community to undertake in-depth risk analyses of nuclear deterrence and, if the results so indicate, to raise an alarm alerting society to the unacceptable risk it faces as well as initiating a second phase effort to identify potential solutions.
The proposed studies serve three purposes. First, they will determine if society’s inaction is warranted. Second, if they confirm that action is urgently needed, they will help bring attention to the issue. And, third, they will identify the most likely failure mechanisms, thereby allowing the second phase effort to proceed most expeditiously.

The proposed studies also combine two critically needed qualities that, until now, seemed mutually exclusive. On the one hand, while defenders of the nuclear status quo have criticized a Comprehensive Test Ban Treaty and similar measures as too risky, I see no way to similarly attack studies to learn the risk we face from our current approach. As expressed in Animal House by Farber College’s motto: “Knowledge is good.” On the other hand, if the studies confirm that the risk from nuclear deterrence is thousands of times greater than society can tolerate, they will show that the solution involves a long-term effort that cannot be dropped at the first partial success, as occurred at the end of the Cold War.

More information on the project, its approach, and the role that individuals play is available at That web site also has links to the paper and statement.