Estimates of weapons of mass destruction threats usually focus on the quantity of weapons an adversary possesses. But it’s really the potential for mass destruction that’s important.

In the case of North Korea, its chemical, biological and nuclear weapons could probably kill 1 million people, and perhaps as many as 10 million if employed effectively. The United States and South Korea must be ready to deal with this vast and growing arsenal, should the North turn aggressive or suffer a government collapse.

North Korea appears to have at least hundreds of tons of chemical weapons and may have as much as 2,500 to 5,000 tons. Fired into a densely populated urban area, 1 ton of the chemical weapon sarin could cause tens of thousands of fatalities. Thus, if North Korea possesses mainly sarin, it could potentially cause hundreds of thousands to millions of chemical fatalities.

Less is known about the quantity of biological weapons that North Korea possesses. Still, given the North Korean focus on special forces, which are ideal for delivering biological weapons, it seems likely that North Korea possesses or could produce at least hundreds of kilograms of biological weapons like anthrax (not contagious) and perhaps smallpox (contagious). Each kilogram of anthrax could infect thousands to tens of thousands of people, while smallpox would spread from those initially infected to infect many others. Without proper medical treatment, hundreds of thousands to millions could perish.

North Korea likely has sufficient plutonium and highly enriched uranium to produce five to 30 nuclear weapons or so. Detonated in a densely populated urban area, one North Korean 10-kiloton nuclear weapon could likely kill 100,000 or more people. Moreover, that same nuclear weapon detonated in Seoul could cause perhaps $1 trillion in losses to the South Korean economy over a number of years.

How could the U.S. and South Korean governments have let these threats develop? The United States had hoped that it could convince North Korea to abandon its nuclear weapons by offering a variety of incentives that would help the North Korean people. But the North Korean regime appears to have little real concern for its people, focusing instead on its own survival. And the regime has tied its survival to a public perception of strength rooted in the possession of vast weapons stockpiles.

It is partially in recognition of these threats that U.S. forces are still based in Korea some 60 years after the end of the Korean War. If North Korea at some point decides to attack one or more of its neighbors, South Korea and Japan being the most likely targets, the U.S. military needs to be positioned to act rapidly to eliminate as much of the North Korean WMD threat as possible. The United States must pay particular attention to preventing North Korean WMDs from being proliferated to third parties like terrorist groups that would likely target the United States. U.S. and South Korean air forces would take the initial role in destroying North Korean WMDs, but would face challenges in locating the weapons and making sure they are destroyed and not just scattered by air strikes.

Thus in a North Korean conflict or government collapse, U.S. and South Korean ground forces would need to advance rapidly into North Korea to find and secure the WMDs. Given time, North Korean forces would likely disperse the WMDs, their production means, the WMD scientists and related documentation. At the same time, North Korean ground forces would likely use WMDs to defend themselves, slowing the operation still more. Finding and securing all WMDs in North Korea could take years. U.S. forces would need to remain committed: The cost of such a military operation would be much less than the cost of proliferated WMD being used against the United States.

North Korea has roughly 1,000 tactical ballistic missiles that could be used to attack South Korea, Japan and other areas. This threat motivates the U.S. consideration of deploying the THAAD missile-defense system in Korea. Despite the arguments of opponents, the THAAD interceptors would be able to destroy at least some of the Scud and especially the Rodong missiles that North Korea could use to target South Korea and Japan. Spending even $10 billion on such defenses would appear to be a reasonable trade against the potential cost in lives and damage that just one nuclear weapon could cause.

The bottom line is that the failure of the United States and South Korea to prevent North Korea from gaining significant quantities of WMDs saddles those governments with serious military responsibilities, should North Korea go to war or should its government collapse. Resolving the WMD threat will not be easy. In planning its national security requirements, the United States cannot afford to underestimate the severity of the North Korean WMD threats and the difficulty it will face in resolving them. 

By Bruce Bennett

Bruce Bennett is a senior defense analyst at the nonprofit, nonpartisan RAND Corporation and a professor at the Pardee RAND Graduate School. ― Ed.