This essay examines nuclear proliferation risks across East Asia through both overt military programs and latent civilian capabilities. While North Korea’s nuclear expansion and China’s arsenal modernization dominate attention on the northern flank, the analysis reveals a more complex landscape. South Korea and Japan demonstrate how proliferation pathways emerge through nuclear hedging—Seoul’s pursuit of nuclear-powered submarines and fuel-cycle capabilities, alongside Japan’s substantial plutonium stockpile and advanced civilian infrastructure, create latent nuclear options amid declining confidence in U.S. extended deterrence.

The essay challenges conventional assumptions about Southeast Asia’s nuclear immunity. Despite the 1995 Southeast Asia Nuclear-Weapon-Free Zone Treaty, the region faces growing nuclear exposure through great-power maritime competition, China’s SSBN deployments, AUKUS developments, and increasing conventional missile proliferation. Simultaneously, several ASEAN states are advancing civilian nuclear energy programs driven by energy security and climate commitments, creating infrastructure with dual-use potential.

The central argument emphasizes that proliferation risk now extends beyond weapons programs to encompass the intersection of civilian nuclear technology, strategic dependencies on external suppliers, maritime nuclearization, and regional security deterioration. This creates pathways through which formally non-nuclear states become enmeshed in nuclear risk, threatening regional stability and nonproliferation norms.