Analysis, Foreign Affairs, Military, Nuclear Weapons

The Fifth Test: North Korea Building a Strategic Rocket Force?

Yesterday’s nuclear test, the fifth by North Korea since 2006 suggests that North Korea can arm a missile with a nuclear warhead. And that may portend a significant change in how the United States thinks about dealing with North Korea.

The test was certainly successful. Estimates of the size the nuclear test – measured just like an earthquake – vary among the groups that monitor the globe for earthquakes and nuclear tests. The U.S. Geological Survey estimated the magnitude of the event as 5.3, while others, including the Comprehensive Nuclear Test Ban Treaty Organization, estimated the magnitude to be 5.0.

But the important point is that this is the largest nuclear explosion ever for North Korea. The groups that estimate it to be a 5.0 all measured previous tests at 4.9 or below. In terms of the actual size of the explosion, the North Korean nuclear test was ten kilotons or more. That’s the same approximate size as the nuclear weapons dropped on Hiroshima and Nagasaki. There are a number of complications in making a precise estimate of the size of the explosion, but the bomb worked.

Reading North Korea’s statement on the test, they are claiming to have tested the same type of nuclear bomb that Kim Jong-un posed with back in March. At the time, Kim described the device as “standardized to be fit for ballistic missiles.”

The statement released after the nuclear test repeats that wording, noting that the “standardization of the nuclear warhead … has definitely put on a higher level the DPRK’s technology of mounting nuclear warheads on ballistic rockets.” The implication is that this design is not merely to demonstrate a capability, but that it is intended to be produced in significant number and supplied to the Strategic Rocket Force.

One major question is how many of these bombs North Korea might produce. North Korea has a small stockpile of plutonium, about forty kilograms according to the Institute for Science and International Security, and a much more uncertain stockpile of highly enriched uranium. The statement notes that North Korea’s nuclear warheads use “a variety of fissile materials” – the most unambiguous reference to the use of uranium in the nuclear weapons program to date. North Korea, with five nuclear tests under its belt, might be using as little as 2 kilograms of plutonium in each device. That would mean as many as 20 nuclear weapons in the near-term, with more to come. And then there may be all-uranium weapons.

It is hard to escape the conclusion that North Korea is preparing to deploy a force of nuclear-armed missiles. During Kim Jong-un’s time in power, North Korea has created a new “Strategic Rocket Force,” has dramatically increased the pace of missile testing, and begun to conduct operationally realistic tests including night-launches, salvo launches and openly practicing scenarios such as striking ports to prevent U.S. forces from coming to the aid of South Korea. The announcement of a standardized warhead appears to be another step in this direction.

It may be time to reassess what we imagine Kim Jong-un and the North Korean leadership think about nuclear weapons. While there is widespread agreement that North Korean leaders see nuclear weapons as a way to deter a U.S. invasion, North Korean statements also make clear that the role of nuclear weapons is to repel an invasion if deterrence should fail. The deployment of a significant nuclear-armed missile force would imply that North Korea might use nuclear weapons relatively early in a crisis, against ports and airfields to prevent the U.S. from amassing forces as it did against Saddam Hussein in 1991 and 2003. North Korea might see this as a war-winning strategy or hope that significant casualties would force the United States to cease hostilities.

North Korea Nuke Test

The deployment of a significant number of nuclear-armed missiles also raises real challenges for South Korea and alliance management of crises. Although South Korea is investing heavily in missile defenses – not just THAAD, but indigenous systems as well – North Korea appears to be developing a number of countermeasures to defeat defenses. South Korea has also invested in new ballistic and cruise missiles that offer the possibility of decapitating the North Korean leadership before it can order the launch of nuclear weapons. While such a strike might be an appealing alternative to hunting dozens of road-mobile ballistic missiles, it also creates an incentive to be the first to strike.

These questions are not easily answered. But North Korea’s fifth nuclear test makes it far harder to ignore them. BP_bookend

Dr. Jeffrey Lewis is a scholar at the Middlebury Institute of International Studies at Monterey. He is the founding publisher of the Arms Control Wonk blog.

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