South Korea, Conventional Capabilities, and the Future of the Korean Peninsula
In August 2020, South Korea’s defense minister revealed that his country had “succeeded in developing a ballistic missile with sufficient range and the world’s largest warhead weight to protect peace on the Korean Peninsula.” The new “Frankenmissile” is part of Seoul’s conventional counterforce and countervalue strategy, which is meant to hold North Korea’s nuclear weapons infrastructure, as well as its leadership, at risk independently from the United States.
This strategy is often overlooked by policymakers and analysts, who are more focused on discussing Kim Jong Un’s pledges to develop new missile and nuclear capabilities and how the new administration of President Joe Biden should approach the nuclear issue. However, as we highlight in a new article in International Security, South Korea’s strategy increasingly has a determining impact on strategic stability on the Korean Peninsula and on prospects for denuclearization.
Elements of South Korea’s Strategy
South Korea’s approach has three core components. The first two, the Kill Chain strategy and the Korean Air and Missile Defense system, were revealed in 2012 and the third, the Korean Massive Punishment and Retaliation strategy, was announced in 2016 following North Korea’s fifth nuclear test. The Kill Chain strategy entails detecting imminent North Korean missile attacks and then pre-emptively destroying the country’s missile launch capabilities. The Korean Air and Missile Defense is a largely indigenous, layered missile defense system, while the final component — the Korean Massive Punishment and Retaliation strategy — involves the use of multiple kinetic and non-kinetic capabilities to target North Korean leadership facilities following any North Korean attack.
In 2019, the administration of Moon Jae-in renamed the Kill Chain and Korean Massive Punishment and Retaliation strategies in an effort to bolster reconciliation initiatives on the peninsula. However, there were no significant alterations in procurement plans or seemingly in the operational intent of the three components beyond a statement from the government that these capabilities would now be focused on omni-directional threats and not just on North Korea. However, the threat from the north still dominates South Korean strategic thinking and while the Moon government continuously emphasizes engaging with Pyongyang, South Korean investments in advanced weaponry have only intensified during his presidency. South Korea has drastically improved its precision-strike capabilities, investing in a range of advanced intelligence, surveillance, and reconnaissance assets as well as a burgeoning force of air-, sea-, and ground-launched ballistic and cruise missiles.
It is understandable that South Korea would pursue an independent deterrent capability given the benefits it offers. Although a conventional counterforce strategy remains extremely challenging to operationalize, it is likely to have a deterrent effect, as even the slightest chance that an attack could fail or that South Korea could pursue catastrophic retaliation may stay the hand of North Korean leaders. It may therefore reduce the risk of North Korean attempts to “decouple” the United States and South Korea and of a North Korean nuclear attack in the event of the United States abandoning its security commitments on the peninsula. An additional long-term benefit of Seoul developing a deterrent capability is that advanced missile capabilities will bolster its nuclear latency and ease the path to obtaining a credible nuclear deterrent if South Korea ever wanted to build the bomb.
Seoul’s pursuit of a conventional counterforce capability is also, in part, a hedge against U.S. abandonment. To be clear, this hedge is happening with a degree of U.S. consent and support and under the security blanket provided by U.S. conventional and nuclear forces. South Korea is coordinating both its strategy and its acquisitions with the United States and, for the time being, is relying on the United States for crucial intelligence, surveillance, and reconnaissance data. South Korea’s capabilities can work in concert with U.S. forces should an emergency on the peninsula arise. For example, in June 2020, the Korean Defense Minister revealed the existence of joint US-South Korea military exercises aimed at improving joint missile defense responses even though South Korean capabilities are not networked with U.S systems. But, vitally for Seoul, should abandonment occur, South Korea would have an independent defensive capability.
Burgeoning Korean Arms Race
At the same time, South Korea’s counterforce and countervalue strategy may also affect strategic stability on the peninsula negatively by driving an emerging conventional-nuclear arms race. Pyongyang will not let Seoul acquire the capability to neutralize its hard-won deterrent and is seeking to bolster survivability and penetrability vis-à-vis the south. In recent years, North Korea has strongly emphasized developing new short-range missiles and has tested launching several missiles simultaneously in an effort to overcome regional missile defense systems. Indeed, North Korea’s newly announced plans to develop tactical nuclear weapons and its continued pursuit of submarine-launched ballistic missiles should be understood as a part of this arms race. While North Korea’s nuclear efforts were originally driven by the United States, the conventional threat from South Korea is having an increasing effect on the trajectory of the north’s weapons program.
If operated independently from the United States, South Korea’s counterforce and countervalue strategy may also increase the risks of nuclear use during a crisis. Because the strategy is supposed to be employed pre-emptively, it may severely stress leaders in both Seoul and Pyongyang and increase the risks of misunderstandings taking place and mistakes being made. The strategy may further incentivize North Korea to adopt a doctrine and command-and-control arrangements that improve survivability but increase the risks of nuclear use, for example, by delegating launch authority further down the chain of command. In a crisis, Pyongyang’s fears of a decapitating conventional strike from Seoul could create a “use-it-or-lose-it” mindset. Threats against the North Korean leadership including the ruling Kim family may exacerbate some of these risks. With North Korean leaders skeptical about their prospects for survival, they may be extremely cautious about establishing communication during a crisis or conflict and see little reason to negotiate an end to hostilities.
South Korea’s conventional capabilities also present a seldom recognized, but potentially insurmountable, challenge for any efforts to denuclearize North Korea. Even if the Biden administration could somehow persuade North Korea that the United States does not represent an existential threat, South Korea’s qualitatively superior conventional forces provide Pyongyang with a strong incentive to keep its nuclear deterrent. Traditionally, Pyongyang has relied on its large arsenal of artillery aimed at Seoul as a conventional deterrent against both the United States and South Korea. South Korea’s current and planned advanced conventional capabilities will greatly improve its ability to mitigate this threat, putting an even greater premium on nuclear weapons for North Korea.
Consequently, if the United States wants to ensure that any denuclearization initiatives are successful, it may need to persuade South Korea to undertake conventional arms reductions, particularly with regard to offensive capabilities. Even objectives that fall short of denuclearization, such as constraining North Korea’s nuclear ambitions, may be difficult to achieve without limiting South Korea’s buildup. That is a tall order. First, it would be unacceptable to South Korean leaders. Even with a new U.S. administration in place that will be less dismissive of its allies, fears of abandonment remain, leaving South Korea with a strong and understandable urge to develop an independent conventional deterrent. Moreover, many of the capabilities South Korea is acquiring provide it with deterrent options that can also be used against an increasingly assertive China. At a time of rising tensions and great-power rivalry in East Asia, the rational choice for South Korea is to bolster its conventional capabilities, not to weaken them, even if relations on the peninsula change. Second, South Korean arms reductions would potentially undermine other major U.S. objectives. These include not only bolstering deterrence against North Korea, but also greater burden-sharing and strengthening its allies’ ability to stand up to a rising China. In fact, as the recently declassified U.S. Strategic Framework for the Indo-Pacific highlighted, the United States’ has sought to help both South Korea and Japan acquire advanced conventional capabilities.
Consider Conventional Developments on the Korean Peninsula
To fully understand the North Korean nuclear issue, analysts should widen their focus beyond the U.S.-North Korean relationship. While South Korea has been at pains to present itself as a peaceful arbiter between the United States and North Korea in recent years, it is now a powerful, technologically advanced state that is creating its own strategic relationships, not only with the north but with other regional actors. South Korea’s conventional capabilities are now increasingly intertwined with North Korea’s nuclear program and with the massive build-up of conventional systems across the region.
Of course, bringing South Korea’s conventional weapons into discussions about denuclearization further complicates what is already a perennial difficult problem. However, Korea-watchers should accept that it is no longer just about the nukes: Advanced conventional weapons capabilities on the Korean Peninsula will have an increasingly powerful impact on how all East Asian actors understand their future security.
Ian Bowers is associate professor at the Centre for Joint Operations at the Royal Danish Defence College, Copenhagen.
Henrik Hiim is a senior research fellow at the Norwegian Institute of International Affairs.
