The problem with defining likelihood

By Mead Treadwell and Jeremy Thompson

The CTC Sentinel, a publication of West Point’s Combating Terrorism Center, reported in July that at least three times in the last two years, nuclear sites in Pakistan have been attacked by local terrorists: A nuclear missile storage facility at Sargodha and Pakistan’s nuclear airbase at Kamra were attacked in 2007; and in 2008, suicide bombers attacked one of Pakistan’s primary assembly sites for nuclear weapons.

The article considers the question of how secure the nuclear arsenals of Pakistan are from terrorists.

“Pakistan has established a robust set of measures to assure the security of its nuclear weapons,” the article states. “These have been based on copying U.S. practices, procedures and technologies, and comprise: a) physical security; b) personnel reliability programs; c) technical and procedural safeguards; and d) deception and secrecy.”

Though these “robust” measures give a “high degree of confidence” to the Pakistan government that its nuclear arsenal is secure, the article says that “empirical evidence points to a clear set of weaknesses and vulnerabilities in Pakistan’s nuclear safety and security arrangements.”

The author addresses two concerns: The first is that the sites that manufacture, assemble or refurbish nuclear weapons are not as secure as the sites that store the deployed ones. The second concern the author considers is the possibility of collusion.

“It is widely accepted that there is a strong element within the Pakistan Army and within the lead intelligence agency, the ISI, that is anti-Western, particularly anti-U.S., and that there also exists an overlapping pro-Islamist strand…No screening program will ever be able to weed out all Islamist sympathizers or anti-Westerners among Pakistan’s military or among civilians with nuclear weapons expertise,” according to the author.

The question is an important one, as the likelihood of collusion in Pakistan would most certainly affect the likelihood of an EMP attack. Nuclear capability in some form constitutes one of three dots that need to be connected: nuclear capability, delivery technology, and the willingness to carry it out. 

But the measure of likelihood, despite being a very complex and elusive question, is often used to create policy the way numbers are used to illustrate math equations, sometimes out of necessity. It is often asserted that EMP is a high risk scenario, but there is a low likelihood that it would occur; therefore, we should not devote resources to preparing for such a scenario. But measures of likelihood on this scale were not meant to enjoy this kind of certainty, nor is it wise to justify a policy on a likelihood that is based on another likelihood.

The terrorist threat to Pakistan's nuclear weapons

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