ROKing the Boat: US Nuclear Weapons in South Korea?

The main opposition party in South Korea (the centre-right Liberty Korea Party, formerly known as the Saenuri Party), last week changed its official party policy on nuclear weapons. At the party’s general meeting, parliamentary leader Chung Woo-taik announced that should it come to power, the party would support the re-deployment of US tactical nuclear weapons to the southern part of the peninsula.

These weapons were last deployed to the Republic of Korea (or ROK as South Korea is commonly known) during the Cold War, but were removed in 1991. At that time, their purpose was to signal to allies and adversaries that the US was committed to defending regional allies against communism in East Asia.

Calls for the re-introduction of nuclear weapons to the ROK are not new, and past debates have even touched on the possibility of Seoul developing its own independent nuclear capability. Yet those debates were often on the fringes of political parties.

The adoption of something similar as the main opposition’s official policy is, therefore, significant, but can still largely be seen as political posturing. The Liberty Korea Party is on a re-branding mission after corruption scandals involving President Park Geun-hye, its standard bearer, and the party’s subsequent defeat in the presidential elections, which followed her removal and impeachment in May.

This rebranding exercise includes national security policy, where the party is looking to differentiate itself from new President Moon Jae-in, a centre-left politician.

Park’s party is far from returning to power so any possibility of re-deployment is a long way off. Moon is only a few months into a five-year term, his approval ratings are currently steady at 78% and elections are not due until the end of the decade.

Still, Moon has been accused of being ‘too soft’ on North Korea. And as tensions in the peninsula are likely to increase over the next few years, and with Moon’s own policies likely not to change things substantially, the opposition’s radical new approach could gain traction.

The current debate focuses attention on US deterrence and its willingness to stand by South Korea should it be attacked.

As Pyongyang’s long-range missile capabilities develop to the extent that they can target the continental US, questions and doubts over Washington’s willingness to sacrifice, say, San Francisco for Seoul or Buffalo for Busan become much more real.

Re-deploying nuclear weapons to the ROK, or reinforcing US conventional military capabilities there, could therefore provide additional assurance of Washington’s commitment to its ally.

The presence of US nuclear weapons in the ROK could potentially bolster the allied deterrence message to Pyongyang that Washington is committed to using its nuclear force on behalf of South Korea if necessary.

The hope is that US nuclear weapons on the peninsula would deter North Korea from pursuing an escalation from conventional to nuclear forces, rather than driving tensions towards it.

These arguments are neither new, nor unique to East Asia; similar concerns over the threat from the Soviet Union and the willingness of Washington to respond immediately and with force to any such challenge drove the decision to deploy US nuclear weapons to Europe during the Cold War, and continue to be the justification for forward-deployed US nuclear weapons in Europe today.

However, these weapons are designed to counter the most extreme threats posed by Russia, a fundamentally different adversary to North Korea, with a far more complex nuclear doctrine, arsenal and concept of deterrence.

Another key difference is that US tactical nuclear weapons in Europe form part of the wider NATO alliance, a multilateral military pact that has extended nuclear deterrence and mutual defence at its core, while in South Korea such weapons would operate within a wholly bilateral relationship.

So, in a crisis, a NATO ally could expect help from 28 other members, three of which are nuclear weapon states; South Korea is reliant on only the US.

Still, the vital consideration in both contexts is the value that the physical presence of nuclear weapons actually brings. In Europe, many have doubted the value of this presence today in providing credible contributions to regional security.

In South Korea, the debate is as complex, and any decision to re-deploy US nuclear weapons on the peninsula would be subject to heavy domestic, regional and international criticism, without necessarily making a valid contribution to enhancing security.

China, in particular, would see this as a clear US escalation, which further complicates the Korean crisis. Some would argue that this move would send a political message to Beijing that Washington has run out of patience, when in fact China would calculate that the US has run out of sense.

Beijing has already attacked the deployment of a US Terminal High Altitude Area Defense missile defence systems to South Korea, and is sceptical of America’s decision-making on North Korea.

The key question for Seoul is what is more valuable for its security context: increasing the number of deployed US troops; bolstering advanced conventional capabilities in some other way; or hosting tactical nuclear weapons.

While in reality the US could pursue both an increase in conventional and nuclear assets, given the geographical size and proximity of the North and South, and the massive disparity of military capability already at play between the US and the DPRK, it may be that other conventional forces could better address assurance and deterrence concerns.

Either way, there would be a challenge in altering the status quo: any change sends a message. In Europe, this has come to mean the enduring presence of nuclear weapons; in South Korea, such a deployment would require significant shifts in South Korean, regional and US foreign policy. A fundamentally political move from the main opposition party does not change this fact.

In any case, any significant change in US posture on the peninsula that results in an increased presence of military force, nuclear or otherwise, risks rocking an already unstable boat in return for questionable deterrence and assurance benefit.

The reintroduction of US nuclear weapons to the Korean peninsula would not allow the US to do anything it cannot already do from afar, it risks alienating and provoking China, and further destabilises an already fragile security situation with North Korea. In our view, it should be avoided.

The views expressed in this Commentary are those of the authors, and do not reflect those of RUSI or any other institution.