North Korea began 2023 as it had ended 2022 – with some characteristic sabre-rattling in the form of missile tests. Having launched more missiles in 2022 than in any other year, on the morning of January 1 this year, North Korea tested a large new multiple launch rocket system that, according to Supreme Leader Kim Jong-un, can strike any part of South Korea with tactical nuclear warheads.

On the same day, Kim called for the North to “exponentially increase” its stock of nuclear weapons. There has been a substantial reshuffle at the top of the military, including the dismissal of Kim’s number two, Pak Jong-chon, who has been replaced by the chief of the general staff, Rim Kwang-il, as part of an effort to push the military harder to achieve greater readiness and combat capability.

Recent displays of belligerence by Pyongyang have drawn a swift reaction from Seoul. After five drones penetrated South Korean airspace (one violating the no-fly zone over the presidential office in Seoul), the South Korean president, Yoon Suk-yeol, issued the military with a reprimand for not shooting them down and ordered a review of the 2018 Comprehensive Military Agreement with North Korea.

The agreement established air, land and sea buffer zones to reduce the risks of armed conflict. Repeated violations of the agreement have led to speculation that Seoul could cancel the deal. 

Analysts in both Seoul and Washington, meanwhile, are watching developments in Pyongyang carefully, following Kim’s decision in September to update a 2013 law in relation to its nuclear doctrine, which now mandates an “automatic and immediate” nuclear response, putting security on the peninsula on a knife-edge.

Carrot and stick diplomacy

On the Korean peninsula the distances involved are relatively short – the capital Seoul, for example, is only 23km south of the border with North Korea. Early warning against a surprise missile attack is practically non-existent, raising the risk of pre-emptive strikes.

Yoon has declared North Korean denuclearisation to be the minimum requirement for the South to engage with the North economically and on security.

On August 15 last year – South Korea’s Liberation Day – Yoon made an offer with incentives for the North to denuclearise in return for what he called “an audacious plan that will vastly strengthen North Korea’s economy and improve the quality of life for its people”.

Seoul’s principal concern is North Korea’s recent “more hostile and aggressive provocations based on confidence over its nuclear and missile capabilities”. The Yoon government is planning to return to the designation of North Korea as “the enemy” in a national defense white paper due for release this month.

Washington’s role

During the Trump administration, conflict over the cost of US forces based in South Korea and the missile defence system Thaad created severe tensions in Washington’s alliance with Seoul, leading to doubts about the reliability of the US nuclear guarantee. 

Biden has restored some level of confidence – but he is a well-known advocate of nuclear arms control and “no first use” of nuclear weapons and has refused to advocate nuclear deterrence against conventional threats. This is why Yoon and his foreign minister, Park Jin, wanted Biden to highlight the US commitment to nuclear deterrence without success.

During the Trump administration, conservatives in South Korea were increasingly voicing the need for South Korea to develop its own nuclear weapons to counter North Korea. The missile testing as well as Kim’s recent statements have revived these voices. But the Yoon administration knows that any movement toward an independent nuclear deterrent would put its relations with Washington at risk and could even result in US sanctions.

Alternatively, US nuclear weapons could be redeployed on South Korean territory. They were withdrawn by the George H.W. Bush administration in 1991 at the end of the cold war. Yoon raised this as a possibility during his presidential campaign last year, but the Biden administration does not support such a move, which would seriously antagonise China and go against Biden’s political instincts.

The fundamental problem with the approach of the current South Korean government is that it has no chance of success to reduce tensions. Over the past three decades, all efforts to persuade North Korea to forego nuclear weapons have failed – so engagement that is conditional on complete denuclearization is a non-starter.

However, it is conceivable that the South and the North could strike some kind of deal to limit the North’s development of nuclear weapons and scale back its testing and military provocation in return for political engagement and the lifting of some sanctions. South Korea and the US could consider putting this to the test and limit the potential for serious escalation.