October 8th 2016
By Davis Florick – Junior Fellow
North Korea’s most recent missile test, which involved the firing of a submarine-launched ballistic missile (SLBM), elevates the level of instability in Northeast Asia at a time when the regional political climate is already fragile. The launch, conducted along Pyongyang’s eastern coast near the submarine base at Sinpo, traveled roughly 500 kilometers toward Japan. The timing of the test coincided with a meeting among the Chinese, Japanese, and South Korean foreign ministers in Tokyo as well as the start of annual joint military exercises on the Peninsula for Seoul and Washington. Earlier in the year, Kim Jong-un conducted both ground-based missile and underground nuclear tests. While previous demonstrations have been problematic, Pyongyang’s SLBM test—above and beyond the political timing of this event—demonstrates a new, highly destabilizing capability. The potential to move submarines beyond the field of view of regional missile defense systems adds an additional element of surprise to the North’s offensive options. Given Kim Jong-un’s increasingly cavalier actions, the Obama Administration’s potential reexamination of the role and number of US nuclear weapons, and anticipated budget cuts in Washington, Seoul and Tokyo may intensify domestic policy discussions to acquire conventional prompt strike (CPS) and perhaps nuclear capabilities of their own. Such systems may be viewed as more able to deter Pyongyang over the long term by denying benefits and imposing costs.
The relevance of Kim Jong-un’s recent SLBM test lies in the potential to circumvent US and allied nations’ missile defense capabilities. Missile defense relies on radar and other early warning technologies to detect and track a launch. To accomplish this, launch and flight need to occur within the sensor field of view. For instance, the US is deploying a Terminal High Altitude Area Defense (THAAD) battery to Seongju, South Korea. The THAAD radar field of view is 120 degrees. Considering Seongju is in the south-central region of the Republic of Korea (ROK), this asset would presumably have visibility over the North’s landmass. However, should Pyongyang move a ballistic missile submarine off its east coast, that asset could be maneuvered to a location outside of THAAD’s currently planned field of view. Although the battery is movable, reorienting the radar is complex and time consuming. Consequently, a viable SLBM capability could circumvent current regional missile defense systems.
There is also the consideration of response times and range. In the coming years, both Japan and South Korea are expected to purchase the next line of Patriot Advanced Capability (PAC-3) missile defense systems with 360-degree field of view. These will augment THAAD, existing PAC-3 systems, and Japan’s Aegis-equipped destroyers. Taken collectively, these systems will provide quantitative and qualitative upgrades, but as North Korea modernizes its missile systems and submarine capabilities, questions and concerns regarding early warning systems, missile defense range, and the reliability of these capabilities will remain.
One would be remiss not to highlight constraints associated with North Korea’s SLBM system. While the test represents a new capability, challenges surrounding the delivery vehicle and warhead miniaturization remain. The North is reported to have conducted its test from a new, prototype ballistic missile submarine. Referred to as Sinpo- or Gorae-class, it is a diesel-electric vessel with likely one or two vertical missile tubes. Based at the Sinpo South Shipyard, it is likely the only submarine Pyongyang possesses which is capable of launching an SLBM. Considering limitations to the delivery vehicle, it is also important to recall that Pyongyang is unlikely to have miniaturized a nuclear warhead. Regardless of missile body, producing a reentry vehicle capable of fitting on a delivery vehicle is a complicated process. It took Washington until 1960 to operationalize the Polaris missile, its first SLBM. While North Korea has conducted five nuclear tests, miniaturizing the technology to deliver a warhead reliably to a target is not an easy task. Pyongyang still has much ground to cover as it seeks to leverage its missile technology.
Despite constraints, North Korea’s research and development programs have significantly elevated concerns for both Japan and the ROK. Pyongyang’s nuclear weapon expertise appears to have advanced considerably, and its missile delivery vehicles are improving in both accuracy and range. Specifically, the Kim regime is developing submarine-launched and mobile intercontinental ballistic missile (ICBM) systems that could limit advanced warning. Responding to these threats requires timely options. Leaders in both Tokyo and Seoul must consider what capabilities Washington can bring to bear and how those systems might impact US decision makers. On one hand, early warning of a North Korean missile launch against Japan or South Korea may come too late for the US to respond with a conventional asset. On the other hand, launching a nuclear ICBM from the continental US could generate significant political problems as Chinese and Russian detection systems may have trouble discriminating where a US launch is headed. As a result, Seoul and Tokyo could find benefits in possessing timely response options of their own.
CPS would provide senior leaders in both Japan and South Korea with a means to deny North Korea benefits from a first strike. Whether as a ballistic or cruise missile capability, conventional systems are ideal mechanisms to prevent Pyongyang from successfully conducting a launch against either state. CPS could give Japan and South Korea greater latitude in their options and serve to demonstrate resolve to other states in the region. Simultaneously, adding a CPS capability would complicate matters for Pyongyang by denying the benefits of a preemptive strike. Collectively, empowering Japan and South Korea to play a greater role in their own defense would alter Northeast Asian dynamics for the better.
At this juncture it would be reasonable to raise questions about exactly how Japan and South Korea could deny North Korea the benefits of a preemptive strike. This question strikes at the heart of the vulnerabilities surrounding Pyongyang’s land-based forces. All of North Korea’s ballistic missiles require liquid propellant. This type of fuel is more combustible and corrosive than solid propellant, which is what most nuclear states use. In practice, the drawbacks to liquid fuel mean that the North has to fuel its missiles immediately before launch. Fueling has been estimated to take 45 minutes for shorter range assets and even more time for longer range weapons. In addition, the Taepodong missiles use above-ground erectors, and the process to assemble the missile frames and fuel them is estimated to take days. Even hours would pose opportunities for overhead imagery collection so the North’s technologies offer Japan and South Korea opportunities to observe what is going on. Similarly, the KN-08, also referred to as the KN-14, almost certainly uses liquid propellant, requiring fueling just before launch. Collectively, these delays truly reduce Pyongyang’s ability to surprise Seoul, Tokyo, and Washington. As organizations such as 38 North have proven, satellite imagery means that not even the new Sinpo-class submarine at the Sinpo South Shipyard can move with impunity. All of these factors taken together make the likelihood of Japanese and South Korean early warning, particularly of a land-based launched, likely.
Exploring a CPS capability certainly carries political and military utility, but far more significant is nuclear acquisition. Proliferation carries a mixture of positive and negative connotations. However, in light of apparent discussions within the Obama Administration about adopting a “No First Use” (NFU) policy, deterrence dynamics are changing. Specifically, should the US remove a potential first strike option from its strategy, a vitally important asset will be removed from a class of scenarios. From the perspective of Seoul and Tokyo, extended deterrent assurances from Washington would be compromised. Conversely, Pyongyang would be able to escalate tensions with greater freedom of movement, knowing it would be more difficult for the US to respond. By developing their own nuclear capabilities, Japan and South Korea might avoid perceived risks associated with a change in US declaratory policy.
Developing indigenous nuclear capabilities would fundamentally alter Kim Jong-un’s options. Beyond concerns over Washington’s declaratory policy, acquisition on the part of Seoul, Tokyo, or both would present a host of complications for Pyongyang. From a political standpoint, conducting inherently destabilizing actions against Japan, South Korea, or both parties could have much more direct implications. The distance, literal and figurative, that separates the US from Northeast Asia has a way of minimizing the force of the Kim regime’s provocations. With acquisition in the region, decisions made by Pyongyang could be more harmful to the regime. Developing non-strategic nuclear weapons would present a range of delivery and timing options for the militaries of both Seoul and Tokyo.
Already political leaders and domestic audiences in Japan and South Korea are voicing their concerns over the North Korean nuclear program and the potential acquisition imperative. In a recent Chosun Ibo article (a popular newspaper in the ROK) experts stated Seoul could develop a nuclear weapon in one and a half years. Likewise, in April Prime Minister Abe stated the Japanese constitution did not prevent Tokyo from acquiring nuclear weapons. Although he also said a minimalist acquisition strategy would likely be undertaken, the overarching message clearly was intended to demonstrate that Japan had alternatives. While administrations in both states are unlikely to pursue nuclear weapon acquisition at this time, the open discussions on the matter have clearly increased as North Korea’s program has advanced.
Pyongyang’s actions have rapidly altered the decision calculus for Northeast Asian stakeholders. Its development of an SLBM capability, in addition to its progress on other missile delivery systems and nuclear assets, has fundamentally altered the regional security environment. Japan, South Korea, and the US will now have to plan for a new threat, one that could further limit warning and response times. Given concerns over NFU discussions within the Obama Administration and the anticipated defense cuts in Washington, it may be time for Seoul and Tokyo to consider other options. Exploring CPS and nuclear weapons would significantly alter strategic dynamics in Northeast Asia. These capabilities would force Pyongyang to reconsider the impact its actions might have. No longer could the Kim regime rely on US caution as a means to conduct escalatory practices. Given the increased likelihood of Pyongyang being denied benefits and having costs imposed should it pursue runaway escalatory techniques, a more capable Japan and South Korea would better deter the North. Ultimately, for legitimate safety and security reasons, the time may well be approaching when Seoul and Tokyo will pursue CPS and nuclear options.