You know how we’re always hearing that we’re stuck with nuclear weapons forever because the knowledge it took to create them can’t be unlearned? Those who believe that disarmament is both dangerous and pointless make the case that sufficiently threatened, a state that once possessed nuclear weapons can always restart the production lines. But, however obvious that may seem, perhaps it’s not quite so straightforward.

In November 2010 the Hudson Institute published a paper by fellow Christopher Ford entitled Nuclear Weapons Reconstitution and its Discontents: Challenges of “Weaponless Deterrence”. The phrase in quotes, also known as “virtual deterrence,” means that, even if state were to reach something approximating Global Zero, they could still deter each other with the ability to ramp up production of their nuclear weapons should they decide a national-security crisis warranted it. But exactly how viable is that?

In a section of his paper titled “The Problem of Re-Learning,” Ford writes:

. . . a former nuclear weapons possessor would need to take careful account of the fact that in an arcane and sophisticated arena such as nuclear weapons design, it can be terribly hard to re-learn after a long absence what one was previously able to do. It may be the case, as Jonathan Schell has argued, that “the knowledge” of how to make nuclear weapons cannot be erased from the world, but one must qualify this by an appreciation that there are a great many different levels of knowledge of nuclear weapons design.

For example, preserving the knowledge of how to make

. . . a ballistic missile re-entry vehicle that must not only be fairly small but also carefully engineered for mating to and precise detachment from its booster under the demanding physical and environmental circumstances of trans-atmospheric travel [is a] demanding requirement. If one were additionally constrained by [a prohibition against building] “new nuclear weapons,” . . . the requirements would be tougher still. According to some experts interviewed for this study, quickly and reliably rebuilding present U.S. “legacy” designs years from now — and with a workforce none of the members of which had been involved in building or testing them in the first place — might scarcely be possible at all.

Ford refers to this as a problem (for plans for weaponless deterrence, anyway). In fact, it provides some hope that nuclear knowledge can be, if not unlearned, too rusty and dusty to be of any real use. In the end, weaponless deterrence may turn out to be ineffective as a last resort in the event of abolition. Neither may nuclear knowledge prove to be as much a barrier to disarmament as it now seems.