Jun Bong-geun and APLN Policy Fellow Joel Petersson-Ivre summarise the findings of APLN’s series of essays that examine regional views of potential South Korean nuclear armament. The authors propose that, to prevent South Korea from going nuclear, regional states should strengthen the non-proliferation regime, deepen their understanding of the drivers and constraints of nuclear proliferation, and support inter-Korean reconciliation and dialogue to address Seoul’s security concerns. 

APLN Associate Fellow Karla Mae Pabeliña analyses how the Philippines would react to South Korean nuclear proliferation. While the Philippines would likely follow UN-imposed sanctions, it would avoid unilateral measures due to its strategic ties with South Korea. She emphasises that, despite potential tensions, the Philippines would continue advocating for peace on the Korean Peninsula and promoting dialogue through ASEAN platforms.

Andhika Prawira and APLN Policy Fellow Elaine Natalie argue that South Korea’s potential nuclear armament could significantly strain its relationship with Indonesia, a strong advocate of nuclear non-proliferation and regional stability. Such a move would destabilise the Asia-Pacific, undermine Southeast Asia’s Nuclear-Weapon-Free Zone, and potentially trigger a regional arms race. Despite their robust economic and strategic cooperation, Indonesia would prioritise regional stability and the integrity of the non-proliferation regime over its bilateral relationship with Seoul.

Enkhsaikhan Jargalsaikhan, former Permanent Representative of Mongolia to the United Nations, outlines Mongolia’s options if South Korea were to go nuclear. While Mongolia would comply with any UN Security Council sanctions, its ability to respond constructively depends on a cohesive international response, and particularly a unified opposition from the UNSC. He warns that South Korea’s nuclear armament would weaken the NPT regime, destabilise regional security, and contradict Mongolia’s long-standing commitment to denuclearisation in Northeast Asia.

Akira Kawasaki and Keiko Nakamura examine Japan’s potential response to a nuclear-armed South Korea and argue that the assumption of a domino effect – where South Korea’s nuclear armament would trigger similar actions in Japan and Taiwan – is overly simplistic. Instead, Japan’s experience in cultivating robust civil society resistance to nuclear weapons can be shared with South Korea to help prevent nuclear proliferation. Through dialogue and education, Japan and South Korea can advance a shared vision of security without nuclear weapons.

Joel Petersson Ivre argues that the South Korean debate on nuclear armament needs a more vocal anti-nuclear weapons movement that can strengthen ties with political allies, build partnerships across the political spectrum, communicate the costs of developing nuclear weapons to the public, and explore alternative security solutions.