Tensions are escalating in Northeast Asia as North and South Korea engage in a rapidly intensifying arms race focused on nuclear-powered submarines. This development follows significant shifts in the United States’ security strategy in the region, prompting both nations to bolster their naval capabilities.
On October 5, 2023, state media in North Korea announced the unveiling of a new submarine, described as an “8,700-ton nuclear-powered strategic guided missile submarine.” This marks the first time North Korea has disclosed the weight and appears to confirm the completion of the submarine’s hull since it signaled its intentions to develop nuclear submarines in 2021. North Korean leader Kim Jong Un stated that the new vessel is intended to protect the nation against “the negative security situation that has come as a present reality.”
The announcement comes as South Korea accelerates its own nuclear submarine program. Following a green light from former President Donald Trump in October 2023, South Korea has taken significant steps towards acquiring nuclear capabilities. A pan-government task force was established in Seoul, and National Security Adviser Wi Sung-lac indicated that South Korea will seek a pact with the U.S. to secure military-use nuclear fuel.
In the context of North Korea’s expanding nuclear threats, South Korea has pursued nuclear submarines for decades. The urgency has heightened as North Korea has developed submarine-launched nuclear missiles and claims to have created a nuclear-capable torpedo. South Korean Defense Minister Ahn Gyu-back acknowledged the limitations of conventional, diesel-powered submarines, stating they “can’t compete with nuclear subs North Korea is building in underwater endurance and speed.”
U.S. Strategy and Regional Dynamics
The U.S. anticipates that South Korea’s future nuclear submarines will serve a dual purpose: countering North Korean threats and addressing the growing influence of China. During a visit to Seoul in November 2023, Admiral Daryl Caudle, the chief of naval operations of the U.S. Navy, noted that it is “a natural expectation” for South Korean submarines to align with U.S. strategic objectives regarding what it identifies as its “pacing threat,” namely China.
President Lee Jae Myung has also addressed concerns regarding China’s military expansion. In a summit with Trump, he remarked on the limitations of diesel submarines, stating that their “limited underwater range restricts our ability to track subs on the North Korean or Chinese side.” Retired South Korean navy captain Yoon Sukjoon emphasized that expanding South Korea’s nuclear submarine operations into Chinese waters could enhance strategic deterrence against the Chinese Navy’s activities in the Indo-Pacific region.
Despite these military ambitions, South Korea remains cautious about openly suggesting confrontation with China, its largest trading partner. Following Lee’s comments, his office clarified that remarks regarding submarines referred to operations in proximity to North Korea and China, not direct threats to Chinese vessels.
Public Sentiment and Strategic Shifts
Public opinion in South Korea reflects a nuanced approach to military readiness. According to a recent survey, a majority of South Koreans believe the nation should maintain neutrality in the event of a serious conflict between the U.S. and China. Meanwhile, there is significant support for South Korea’s pursuit of nuclear armament, even if it risks international sanctions or the withdrawal of U.S. troops.
Political scientist Kim Heungkyu from the China Policy Institute at Ajou University highlighted the growing unease among South Korea and Japan regarding China’s influence. He noted that as the U.S. shifts its defense focus closer to home, its allies are increasingly skeptical of America’s security commitments in Asia. A poll conducted by the Asan Institute in March revealed that less than half of South Koreans trust that the U.S. would respond with nuclear weapons if North Korea were to attack the South.
Kim argues that in a new international order without a strong U.S. presence in the Western Pacific, South Korea must develop a survival strategy that includes nuclear weapons. He posits that nuclear submarines could serve as “an entry point toward a much bigger goal” of nuclear armament. Although the South Korean government maintains that it does not seek nuclear capabilities, ongoing discussions with the U.S. about enriching uranium and reprocessing spent fuel raise concerns about its long-term intentions.
As the arms race between North and South Korea unfolds, it reflects broader geopolitical shifts in the region, with implications that extend beyond the Korean Peninsula. The future of security in Northeast Asia hangs in the balance as both nations pursue advanced military capabilities while navigating complex international relationships.
