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A Nuclear Testing Colloquy: Pierce Corden and Chris Ford


Dr. Pierce Corden recently wrote to this website to offer a counterpoint to the views expressed in Dr. Fords August 16 posting “Nuclear Testing and the Noncompliance Report,” discussing nuclear test moratoria and the Comprehensive Test Ban Treaty (CTBT).  Cordens comments, and Ford’s reply, are reproduced here with their permission, in order to offer NPF readers the benefit of this dialogue.

Pierce Corden served from 2002-07 as Director of Administration for the CTBT Organization’s Preparatory Commission in Vienna .  A biography of Ford, a former State Department official who is now a Senior Fellow at Hudson Institute and runs this website, is available at the bottom of this page.


Chris Ford’s posting of August 16 on the Department of State’s July 2010 Compliance Report focuses on the Report’s section dealing with compliance with the current moratoriums on nuclear tests, which for China, France, the UK, the U.S., and Russia, have been in place since at least 1996.  The discussion about “compliance” with these moratoriums usefully points out the apparent inconsistency between the Report’s statement that the scope of none of these policies has been “publicly defined,” but that there is no evidence that there have been activities inconsistent with the moratoriums (unless the administration has private information about their scope).  But it would be rather startling to learn that the scope of the U.S. moratorium is inconsistent with the scope of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) as it applies to testing in any place not governed by the 1963 Limited Test Ban Treaty; even more so if the US was continuing to conduct tests under such a different understanding.

Chris Ford broadens his posting to address a different issue, the CTBT, and its treatment by the Strategic Posture Review Commission’s 2009 report.  I find it difficult to agree with the posting’s linking the Compliance Report’s treatment of the test moratoriums to the Commission’s separate accounts of why they support or oppose US ratification of the CTBT.  While the Compliance Report’s discussion is brief, it cannot be a precedent for compliance judgments of an in-force CTBT.

With regard to the posting’s extended discussion of the Commissioner’s differing views, Chris Ford says that the proponents of Treaty ratification did not contest the opponents’ views about apparent Russian and possible Chinese testing under their moratoriums. However, the differing views were inserted in the Commission’s report as free-standing, short summaries of those views, without either side having the opportunity in the report to contest them.  I don’t think it correct to conclude that the proponents do not consider low-yield explosions, in particular up to hundreds of tons, to be a serious matter for the moratoriums, let alone the CTBT.

Chris Ford continues with a discussion of the fact that there is no explicit definition of a nuclear explosion contained in the Treaty, and draws from that fact the conclusion that under the Treaty low-yield nuclear testing could continue.  But the lack of a definition does not mean that the negotiators in Geneva did not agree on the Treaty’s scope.  As the American negotiator, Amb. Stephen Ledogar, and Secretary of State Albright testified before the Senate Foreign Relations Committee in October 1999, agreement on the scope, to include nuclear explosions of any yield down to zero, was reached.  Were Russia or China to engage in testing at any yield under an in-force CTBT, to include yields of hundreds of tons, they would be in violation of the Treaty.  Different interpretations of the scope of the Treaty, its most basic element, are simply not supported by the negotiating record.  There is no basis for “subjective definitional gamesmanship.”

It is worth noting that the 1963 Limited Test Ban Treaty, whose formulation of scope was the basis for the formulation in the CTBT, also does not contain a formal definition of a nuclear explosion.  Nor, for that matter, does the NPT contain a definition of a nuclear explosive. In neither case has this posed a difficulty.

It is not likely that the administration found itself in an awkward position with the Commission CTBT opponents raising an issue of “apparent” or “possible” testing in 2009.  The Commission is not the first to raise the issue in public.  The issue has been in the public domain since at least October 1999, when in addition to the SFRC hearing noted above, the Senate Armed Service Committee and the Senate floor debate leading to the refusal of the Senate to consent to ratification of the Treaty took place.

In the SASC hearing on Oct.6 1999, Senator Inhofe refers to a Washington Post story:  “Twice last month, the Russians carried out what might have been nuclear explosions at its Novaya Zemlya testing site in the Arctic.  The CIA found that the data from seismic sensors and other monitoring equipment were insufficient to allow analysts to reach a firm conclusion about the nature of events.”(p.35)

In the SFRC hearing on Oct. 7, Senator Shelby, in his prepared statement, says “The Washington Post last weekend reported that Russia continues to conduct possible low-yield nuclear tests at its Arctic test site, reportedly in order to develop a new low-yield weapon that will be the linchpin of a new Russian military doctrine.  The Washington Post also reported that the CIA cannot monitor such tests with enough precision to determine whether they are nuclear or conventional explosions.”(p.57)

In the floor debate on Oct. 12, Sen. Kyl introduced into the record an article of the same date from the Washington Times.  Regarding Russian and Chinese testing sites, the article says “U.S. intelligence agencies suspect the two locations were used recently for small nuclear test blasts.”(p.S12369)

If the U.S. government has concluded that there is sufficient reason to be concerned about activities at established nuclear test sites, it would have good reason to raise its concerns with the other party concerned.  There is no public information of which I am aware that this has happened.

-- Pierce S. Corden


Many thanks to Dr. Pierce Corden for pointing out the ways in which the issue of low-yield Russian testing was publicly raised when the CTBT faced Senate scrutiny last time.  To my eye, the shift in language from the 1999 comments he quotes (e.g., “possible” and “might have been”) to the language cleared for release in 2009 by the anti-CTBT Commissioners in the SPRC report (“apparently”) is intriguing.  It suggests the acquisition of additional information and/or the solidifying of analytical assessments within the U.S. Intelligence Community over the intervening decade.  Especially if this turns out to be the case, one might suppose, therefore, that the question of secret testing will receive even more emphasis and scrutiny if the Senate considers CTBT again – though it is far from clear what more, if anything, can be said about this on an unclassified basis.  So far, the most on this subject that I have seen in recent years is from SPRC Commissioner and former Defense Secretary James Schlesinger, who has referred to the existence of “clear intelligence information that others are engaged in activities that we ourselves would not engage in, under the existing rules.”

My point on the definition was not that the United States has not itself been very clear that it views the CTBT as having a strict zero-yield threshold.  It has indeed been extremely clear, and we have also observed the zero-yield principle in our current policy moratorium.  (We have done sub-critical tests, for instance, but I understand we’ve been very scrupulous about not crossing the line into nuclear yield.)

Dr. Corden is right to suggest that the issue of definitions for the moratoria of other NPT nuclear weapons states (NWS) is potentially different from the issue of CTBT definitions.  It is possible, for instance, that Russia and China would adopt the view that their policy moratoria allow some form of low-yield testing, but that the CTBT – if it ever enters into force – would not.  During its proclaimed testing moratorium of 1958-61, the United States apparently conducted “hydronuclear” experiments, which it defined as tests producing energy equating to no more than the detonation of two kilograms of high explosive. These experiments, therefore, actually did produce at least some “yield” – marking our interpretation of that moratorium as being different from the standard we now apply to ourselves under the current moratorium begun by President George H.W. Bush in 1992.  (It was apparently the original U.S. and British negotiating position in drafting the CTBT that the test ban should permit hydronuclear experiments.  When the other three NPT nuclear weapons states [NWS] argued for much higher yield thresholds, however, the only thing upon which people could reportedly agree was “zero.”  Even then, moreover, no actual threshold was written into the Treaty text.)  It is certainly possible, therefore, for a “no-testing” policy moratorium to mean something different from the “zero-yield” standard said to be part of the CTBT.

The problem is, we don’t necessarily know how countries would choose to interpret the CTBT – nor do we have much confidence that the CTBT Organization (CTBTO) in Vienna would have any clue that they were doing low-yield testing even if they did.  (If Russia and perhaps China have indeed done some such testing, its detection presumably represents a U.S. intelligence coup, but no credit seems due CTBTO: the official treaty monitors are apparently none the wiser.)

The NWS have happily encouraged everyone to believe that their moratoria are not functionally different from CTBT adherence – i.e., that these pledges essentially non-mandatory proxies for CTBT compliance. (The Obama Administration is itself no exception to this: the whole point of the oddly ambiguous “testing moratorium” discussion in the 2010 Noncompliance Report seems to be to reassure us about CTBT, encouraging the reader to conclude that the NWS really do keep no-testing promises.)  This suggests, but does not necessarily mean, that the NWS will interpret CTBT as they interpret their moratoria.  Low-yield testing under the moratoria would be worrisome in this regard, insofar as it would raise questions about whether all NWS would regard what we would call low-yield (i.e., non-zero-yield) tests as in fact being prohibited by CTBT.  According to Schlesinger, Russian experts – apparently in discussions with SPRC Commissioners – “have stated that their notion of violating the [CTBT] treaty is if [an explosion] can be detected elsewhere.”  That is hardly reassuring.

As I noted in my first essay on the Obama Administration’s Noncompliance Report, I understand that CTBT supporters make the argument that the Treaty would be in America’s interest even if it does not stop low-yield testing – either on account of definitional ambiguity or simply because some NWS choose to cheat by conducting tests below CTBTO’s detection threshold – because CTBT would still make it harder (even if not impossible) for others to develop or improve nuclear weapons.  Indeed, I have sometimes heard it argued that CTBT would give the U.S. and the Russians a net advantage in future nuclear weapons work, since because they possess good simulation capabilities and plentiful empirical testing data from the “old days,” Moscow and Washington would end up better positioned for CTBT-compliant nuclear weapons work than anyone else.  (Thanks in part to the high-performance computers we have exported there, China must be assumed to have fairly good simulation capabilities too, although unless it obtained the computer disks of hydrodynamic “legacy” code data from past U.S. nuclear testing that mysteriously disappeared from the Los Alamos National Laboratory in the 1990s, Beijing presumably lacks a deep pool of past test data.)  If our post-testing “stockpile stewardship” capabilities are good enough, it is sometimes argued – at least privately, in pro-CTBT U.S. circles – why should we not embrace CTBT as a tool for locking in U.S. advantages vis-a-vis most other nuclear players?

This line of argument is complicated, however, by the issue of low-yield nuclear testing, because such testing holds the potential to change the very relative positions that it is suggested CTBT would advantageously “lock in.”

CTBT skeptics (among them the anti-CTBT Commissioners on the SPRC) worry that either through CTBTO-undetectable cheating or simply through legal gamesmanship, countries willing to engage in low-yield testing would have continuing access to a source of basic nuclear weapons research that we would – in scrupulous compliance with our rigorous view of CTBT as prohibiting tests with any nuclear yield whatsoever – deny ourselves.  Since we aren’t doing it ourselves and presumably don’t know precisely what Russia or China might be learning from such testing, it is hard to say what specific advantage (if any) such tests would provide, especially over the longer term.  But this very uncertainty is itself troubling to CTBT skeptics.

This is not necessarily a conclusive argument against CTBT, of course, for Moscow and Beijing – not to mention other countries – would be free to do quite a bit more testing if the CTBT movement fell apart than they would under the Treaty.  (If they are indeed doing testing today, after all, it is presumably only at very low yield levels precisely because they do not wish to be seen to be violating their moratoria or playing games around the CTBT.)  This is why, as I noted, the pro-CTBT Commissioners seem to have felt it really doesn’t matter – for purposes of CTBT ratification, anyway – whether such secret testing is occurring.  If we have taken ourselves forever out of the testing business for political reasons, the argument would go, having others face more constraints on account of the Treaty (even if these prove to be notably imperfect constraints) is surely better than their facing fewer constraints.

Nevertheless, the question of secret testing does make the CTBT case more problematic – and surely a somewhat harder sell in the U.S. Senate if indeed it ever shows up there at all.  As Dr. Corden points out, the secret-testing question was already a serious worry for U.S. Senators in 1999, when the issue seems to have concerned only Russia.  Now, to judge from the debate in the 2009 SPRC report and Schlesinger’s comments, the U.S. assessment vis-a-vis Russia may be more emphatic, and China is apparently a question as well.

It is also worth noting that it may not be safe to assume that everyone will agree on precisely what zero nuclear yield means in the first place.  As a general matter, measuring yield is apparently intrinsically somewhat uncertain, to the extent that U.S. and Soviet negotiators felt compelled formally to agree in connection with the Threshold Test Ban Treaty (TTBT) of 1974 – which established a 150-kiloton limit – that occasional slips above the prescribed threshold “would not be considered a violation of the Treaty.”

To be sure, whether or not any nuclear yield will occur at all might be easier to predict than precisely what a given weapon’s first tested yield will be.  (In the days of nuclear testing, observed yields certainly did not always correlate to predicted yield: sometimes they were less, and sometimes more.)  The TTBT, however, still had to struggle with the idea of when a nuclear explosion had occurred at all, insofar as the TTBT Protocol contained certain notification and verification provisions that might kick in whenever any nuclear test took place.  (If one Party did not plan any particularly large nuclear tests, for instance, the other Party had a right under Paragraph 2 of Section III to conduct hydrodynamic yield measurements on two of the highest-yielding tests that were to take place within a certain period of time.)  As the pace of testing slowed down, this presumably gave both sides some incentive to squeeze in as much experimentation as they could without it constituting a TTBT-recognized test at all.  The definition of a “test” was thus potentially important.

Significantly, however, the TTBT negotiators did not choose (or were unable) to agree on defining a test on the basis of the presence or absence of yield: they opted instead to define it as an “explosion” (or a series of near-simultaneous explosions within a certain radius) in which “nuclear energy” was released from “an explosive canister.”  An explosive canister, in turn, was defined as “the container covering for one or more nuclear explosives.”  Under TTBT, therefore, setting off a device that actually produced a small nuclear yield wouldn’t actually be a “nuclear weapon test” at all if the resulting energy could be kept inside some kind of containment vessel.  (Such containment might be feasible at very low yields: one might imagine a hypertrophic version, perhaps, of the sturdy metal spheres sometimes used by police bomb squads for containing suspicious packages.)

To be sure, as Dr. Corden notes, even though the CTBT doesn’t define a nuclear explosion, the negotiating record for the CTBT is said to be quite clear that the Treaty prohibits any explosive yield whatsoever.  Assuming that this is true, however – and any effort to rely upon the negotiating record in this regard would presumably have to be accompanied by giving today’s Senators access to that record (a step which the Obama Administration has so far refused to take with respect to its new strategic deal with Russia) – that’s still not quite the same thing as having the text itself be clear.  As we have seen, its drafters seem to have carefully avoided a definition.  (One might ask oneself why.)

Indeed, the notion of “zero-yield” may itself be subject to some interpretation. Fission energy release presumably isn’t the key in and of itself, of course, because a civilian nuclear power reactor also produces energy from fission.  One must also look at energy release over time.  According to Richard Garwin and Vadim Simonenko, for instance, a nominal reactor might fission a ton of heavy nuclei per year, equating to some 17 megatons of explosive yield.  That’s a great deal of energy, of course, but nobody considers this an explosion, because the energy release takes place over such a long time.  Yet even such a notional power reactor might produce enough energy in a millisecond to equate to about 500 grams of high explosive.  Since it would be churlish to consider this a CTBT-violative non-zero “yield” of 500 grams, one should presumably further refine the definition by pointing out that reactor energy is produced on a sustained and steady-state basis, rather than in the sort of destructive spasm one would normally associate with an “explosion.”  But how quickly must some quantum of energy release occur in order to be considered an explosion that has yield, or what sort of destruction of the energy-producing elements must occur?  Is this spelled out in the negotiating record, or generally understood in the scientific community?  And what are the practical implications, if any, of adopting different definitions?  (It would be helpful to hear from NPF readers on this ....)

If the Obama Administration wants to head off seeing the question of foreign involvement in what the U.S. would interpret as low-yield testing imperil CTBT’s prospects in the Senate once again – as Dr. Corden notes that it did in 1999 – is there anything Washington can do?

I suppose one might imagine that if the Administration were committed to achieving restrictions on nuclear testing in ways that serve U.S. interests and those of international peace and security – as opposed, for instance, to supporting CTBT for its own sake, as a sort of talismanic or theological goal – it might try to mitigate the potential political impact of this problem by adopting a sort of “most-favored nation” (MFN) rule for CTBT interpretation.  Such an approach might see us articulate our belief that the best answer for interpreting the Treaty’s test ban threshold is “zero” yield (defined in some way we would explain in public), but that in the event that everyone does not entirely agree – something which we would declare ourselves willing to judge not only according to others’ statements but also on the basis of our best understanding of their actions – Washington would not feel constrained to hold itself to a definition more stringent than the most permissive one we infer has been effectively adopted by any other state.  If Russia or China felt it permissible to undertake low-yield testing, therefore, we would deem ourselves similarly unconstrained.

This wouldn’t mean that we would necessarily begin such testing upon detecting foreign activity of a sort inconsistent with our view of the Treaty threshold, of course.  Yet this “MFN” approach would let others’ apparent legal flexibility empower us to reserve the option of protecting ourselves a bit better against potential technical surprise by mirroring such activity.  With luck, such a gambit would help “deter” legal slipperiness on others’ part, and encourage fidelity to a more serious zero-yield standard.  If the CTBT’s negotiating record indeed makes a strict zero-yield interpretation both legally inarguable and administrably clear, moreover, this “most-favored nation” approach would presumably have no impact, because all States Party would agree with America’s rigorous view of the threshold.

If urging (and modeling) strict compliance with a congenially robust interpretation didn’t work, however, this “MFN” approach might somewhat mitigate the dangers inherent – particularly over the longer term – in our otherwise being asymmetrically constrained by the Treaty.  It would, in a sense, offer a way to respond to the detection of limited foreign activity that avoids an otherwise stark choice between the risks of de facto acquiescence and the politico-legal upheaval of formal CTBT withdrawal.  According to Schlesinger, potential differences in how CTBT States Party might interpret its rules are a major concern among those skeptical of the Treaty, and in fact “[m]any of the members of the [Strategic Posture Review] commission would strongly support the CTBT if there were clarification of those rules.”  Absent such a compelling and authoritative clarification, could an “MFN” approach help cross this bridge?

This, however, is really a subject for another day, should the issue of CTBT ratification ever come up again in the U.S. Senate.  It may not.  In fact, this issue may remain a purely academic debate, given that even the CTBT’s supporters seem to see Senate ratification receding into the distant future, and actual entry into force (EIF) – after similar ratification by China, India, Iran, North Korea, and Pakistan – as being notably unlikely.  (Even U.N. Secretary General Ban Ki-Moon, in what must surely be seen as a vote of low confidence in the Treaty’s own specified terms for EIF, has recently suggested the need to explore “an alternative mechanism” for bringing a test ban into effect.)  Nonetheless, I again offer my thanks to Dr. Corden for his insights.  I hope NPF readers will find our colloquy both interesting and valuable, and I encourage further feedback.

-- Christopher Ford

About Dr. Ford

Dr. Christopher Ford served from January 2018 until January 2021 as the U.S. Assistant Secretary of State for International Security and Nonproliferation. For the last 15 months of this period, he additionally performed the duties of the Under Secretary of State for Arms Control and International Security. Before this service at the State Department, he served as Special Assistant to the President and Senior Director for WMD and Counterproliferation on the U.S. National Security Council staff, and before that as Chief Legislative Counsel for the U.S. Senate Foreign Relations Committee, Chief Investigative Counsel for the Senate Banking Committee, Republican Chief Counsel for the Senate Appropriations Committee, Senior Fellow at Hudson Institute, U.S. Special Representative for Nuclear Nonproliferation, Principal Deputy Assistant Secretary of State, Minority Counsel and then General Counsel to the Senate Select Committee on Intelligence, and Staff Director of the Senate's Permanent Subcommittee on Investigations. A graduate of Harvard (summa cum laude), Oxford (as a Rhodes Scholar), and the Yale Law School, Dr. Ford was also ordained by Roshi Joan Halifax of the Upaya Zen Center as a lay chaplain in a lineage of Soto Zen Buddhism. He was a jujutsu student of the late Grandmaster Dong Jin Kim of the Jigo Tensin Ryu lineage, and is a member of Dai Nippon Butoku Kai with Sandan (3rd degree black belt) rank. Dr. Ford served from 1994 until 2011 as an intelligence officer in the U.S. Navy Reserve, and is a member of the International Institute for Strategic Studies, Chatham House, and the Council on Foreign Relations. In September 2017, he was promoted by Queen Elizabeth II of England to the rank of Commander in the Most Venerable Order of the Hospital of Saint John of Jerusalem. Dr. Ford is the author of the books "China Looks at the West: Identity, Global Ambitions, and the Future of Sino-American Relations" (2015), "The Mind of Empire: China's History and Modern Foreign Relations" (2010), and "The Admirals' Advantage: U.S. Navy Operational Intelligence in World War II and the Cold War" (2005). He also co-edited "Rethinking the Law of Armed Conflict in an Age of Terrorism" (2012). For a list of his publications, see The views he expresses on this website are entirely his own, and do not necessarily reflect those of anyone else, in or out of government.
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