When South Korean President Lee Jae-myung took office in June 2025, he inherited a Korean Peninsula frozen in hostility. His response was a ‘peace first’ policy that puts engagement and risk reduction before denuclearisation — a departure from decades of South Korean orthodoxy.

For South Korea, unification with North Korea has long been not only a national aspiration, but also a constitutional mandate. Article 4 of the Constitution enshrines unification through peaceful means as a national mission. Yet after around 80 years of division, unification feels more like an echo from a distant age than a viable goal. The real question now is not how to wind back the clock, but how to prevent the peninsula’s nuclear-tinged hostility from removing any hope of peaceful coexistence.

The nuclear threat posed by North Korea is evident. North Korea first announced its intention to withdraw from the Non-Proliferation Treaty in March 1993. While it suspended this withdrawal and agreed to halt its nuclear programme under the 1994 Agreed Framework, North Korea withdrew from the Non-Proliferation Treaty in 2003 and conducted its first nuclear test in 2006. This established North Korea as a nuclear-armed state by default, though South Korea and the international community withhold formal recognition.

North Korea’s nuclear capability presents South Korea with a dilemma. Diplomatic engagement that ignores nuclear growth is neither prudent nor politically sustainable. Yet making denuclearisation a prerequisite for engagement leaves little room for dialogue.

The last period of substantive, high-level inter-Korean dialogue was during the 2018–19 Korean peace process, which saw three inter-Korean leaders’ summits in April, May and September 2018. That year’s inter-Korean summits, the US–North Korea meetings in 2018 and 2019, as well as the brief three-party encounter in the demilitarised zone at Panmunjom in 2019 raised hopes for a new peace architecture but ultimately failed to alter the peninsula’s underlying security structure.

Since coming to office in 2025, Lee has articulated a ‘peace first’ policy, in which engagement and risk reduction are prioritised over denuclearisation. In his 2025 Liberation Day address, Lee declared, ‘we affirm our respect for the North’s current system, aver that we will not pursue any form of unification by absorption and assert that we have no intention of engaging in hostile acts’. Rather than a renunciation of denuclearisation, this reflects Lee’s view that peace-building, risk reduction and a freeze on further nuclear growth must precede any eventual settlement of the nuclear question.

In his 2026 Liberation Day address, Lee built upon these principles by outlining three goals — ‘inclusive’, ‘stable’ and ‘responsible’ peaceful coexistence. He proposed launching dialogue to replace the inter-Korean armistice with an enduring peace regime. Lee suggested that this dialogue could also consider practical measures to curb advances in North Korea’s nuclear capabilities.

This approach continues South Korea’s pursuit of peaceful unification, yet acknowledges that Pyongyang no longer views inter-Korean relations as a special relationship. Since its ‘two hostile states’ declaration in late 2023, North Korea has treated South Korea as an adversary in a state-to-state relationship and has abandoned unification as a shared aim. So for South Korea, peaceful coexistence is no longer merely a stage on the road to unification — it is the immediate condition for preserving that road.

While peace has always been emphasised and linked to unification, Seoul and Pyongyang hold different interpretations. Pyongyang views peaceful unification as code for covert absorption, whereas Seoul views it as unification achieved through peaceful means. Lee’s ‘peace first’ agenda aims to resolve this discrepancy. But the publics in both Koreas will require Lee to outline concrete prospects for what peaceful coexistence means.

Pyongyang’s response to Lee’s Liberation Day speech has been silence. North Korea’s deepening military relationship with Russia diminishes its incentive to improve relations with Seoul. At the same time, US–China strategic competition is narrowing South Korea’s room to manoeuvre while expanding North Korea’s leverage. The US–South Korea alliance, a cornerstone of deterrence on the peninsula, appears to have deteriorated and faces new uncertainty. These developments are not proof of an alliance rupture, but they complicate Seoul’s effort to combine engagement with credible deterrence and cast doubt on the future of Lee’s ‘peace first’ approach.

It is unrealistic to expect dramatic changes in inter-Korean relations simply because Seoul has changed its language and made a proposal. The realisation of Lee’s proposal will depend on whether his government produces concrete policy details. It will require reliable communication, practical incident prevention arrangements, restrained rhetoric, a humanitarian approach and a credible proposal for a nuclear freeze. It will also depend on whether North Korea finds any reason to respond.

‘Peace first’ cannot deliver unification on its own. But if it prevents the nuclear and military confrontation from hardening into permanence, it may keep peaceful unification from simply remaining a constitutional phrase.

Giwoong Jung is Vice Head of HK+ National Strategies Research Project Agency and HK Professor at the Center for International Area Studies, Hankuk University of Foreign Studies.