The Rising Nuclear Tensions in Northeast Asia
China’s military buildup, but also North Korea’s nuclear threats, have led to South Korea and Japan reinforcing their defenses. This may well lead to an arms race in the Indo-Pacific.
Japanese Prime Minister Fumio Kishida’s trip to Europe and North America in January was a reflection of the growing tensions and the shifting strategic landscape in the Indo-Pacific region. The tour, which took him to France, Italy, the United Kingdom, Canada, and the United States was meant to lay the groundwork for the G7 summit that the Japanese government will host in Hiroshima in May. But it also underscored Japan’s new security concerns, as Kishida took the opportunity to strengthen military ties with partners and to explain the key national security reforms the country has undertaken over the last few weeks, which will see Japan double its defense spending by 2027.
China’s more assertive military posture in the region and the growing concerns over a potential Taiwan conflict are the main driving forces behind this shift—China is described as Japan’s “greatest strategic challenge” in Japan’s new National Security Strategy. But it is by no means the only one. North Korea remains a key source of concern for Tokyo, and also for Seoul, and its accelerating nuclear and missile programs are ratcheting tensions and increasing the risk of nuclear proliferation in Northeast Asia.
Responding to Rising Threats
Pyongyang conducted over 70 ballistic missile tests in 2022, marking a new record. In a belligerent speech in December 2022, the North Korean leader, Kim Jong-Un, not only made clear that this upward trend is likely to continue, but he also announced that North Korea would start mass producing tactical nuclear weapons. Many also expect the regime to conduct its seventh nuclear weapons test at some point this year.
In response to this and other challenges, Japan has already announced its intention to develop counterstrike capabilities to face off potential threats from North Korea or China. Meanwhile, South Korean President Yoon Suk-yeol has floated the possibility of South Korea acquiring nuclear weapons if the situation on the Korean Peninsula worsens. While he was careful to emphasize that this was not government policy, public support for the idea is already very high in South Korea and has trended upward over the last few years, with some surveys putting it at over 70 percent today.
These developments in North Korea, alongside China’s growing military power, have pushed Seoul and Tokyo closer to their Western partners, as demonstrated by Kishida’s trip and both nations’ growing engagement with NATO. Jens Stoltenberg, the transatlantic alliance’s secretary-general, welcomed this on a visit to Tokyo on January 31, speaking of the “most severe security environment since the end of World War II.”
Russia’s war against Ukraine, however, has also had some profound implications for the Indo-Pacific. It has led to a realization in both Tokyo and Seoul of the importance of stepping up military preparedness before a conflict erupts, as well as of their vulnerability in the face of nuclear-armed states in the region. As the environment becomes more challenging and threats increase, Japan and South Korea will have to adapt in order to bolster their military and defense capabilities, fueling an arms race that runs the risk of turning nuclear. Confidence in the US nuclear umbrella is declining in both nations, and Yoon’s words are a clear warning: South Korea may go at it alone if the situation does not improve.
Beijing Sees the Risks but Blames the US
These dynamics have not escaped the attention of Beijing, which has accused Tokyo, Seoul, and Washington of inciting confrontation and treating the Asia-Pacific as a “wrestling ground for geopolitical competition.”
But beyond the rhetoric, Beijing remains concerned about North Korea’s nuclear program, which it sees as an unwanted source of instability in the region. In an ideal scenario, China’s ultimate goal is very much like Washington’s or Seoul’s: a peaceful solution to the conflict and the denuclearization of the peninsula. But as North Korea’s neighbor, and concerned that the US may be building a coalition to contain its rise, China will do all it can to prevent the collapse of the Kim regime or a major crisis at its borders, even if that means opposing comprehensive sanctions or continuing to support the North Korean regime. Fundamentally, China’s policy toward Pyongyang has long been shaped by its relationship with the US, and that will likely continue.
This means that even though Chinese experts have identified the risk of nuclear proliferation in Northeast Asia as one of the main security risks for China in 2023, they place the blame squarely on the US and its allies, Japan and South Korea. A study on "China's External Security Risk Outlook 2023," published by Tsinghua University’s Center for International Security and Strategy, for example, pinpoints two drivers behind the current crisis: US and allies’ overreactions to China’s development and their inability to effectively respond to North Korea’s security demands. The more that China views the world through the lens of its geopolitical competition with the US, the harder it will be to enlist Beijing’s help to deal with regional or global security challenges.
These new dynamics spell trouble for the region. North Korea will not give up its nuclear program at this point. And China’s rapid nuclear arsenal expansion, as well as its more assertive posture in the region, will not go away either. As neighboring countries respond, nuclear tensions are likely to increase.
Diplomatic efforts to curtail this trend will be an uphill battle this year. While in the past Russia and China may have voted with the rest of the UN Security Council to impose sanctions on North Korea after missile or nuclear tests—even if enforcement was then limited—that seems an unlikely proposition today. Beijing and Moscow already vetoed renewed sanctions on Pyongyang in May 2022 and they are likely to do the same with further attempts. The breakdown of relations with Russia, together with the lower levels of trust between Europe, the US, and China, would also hinder any attempts at renewed multiparty negotiations with North Korea.
To be sure, neither Japan nor South Korea are interested in a nuclear arms race. And few analysts believe that President Yoon will follow through on his remarks. Regardless, the changes in Seoul and Tokyo’s posture are clear indications of their rising threat perceptions and of their wish to pressure the US and other allies into expanding their involvement in the region and especially their defense assurances.
It remains worthwhile to explore diplomatic solutions to this crisis, and Europe would be well served to play a more active role in attempting to encourage or facilitate negotiations, however unlikely these may be. But Europe also has a role to play in security matters. Whether through NATO or bilaterally, it can contribute to deterrence by strengthening security dialogues and cooperation with Japan, South Korea, and other regional partners. This is after all, no less than what it committed to in the European Union’s Indo-Pacific Strategy and the NATO Strategic Concept.
Helena Legarda is Lead Analyst at the Mercator Institute for China Studies (MERICS) in Berlin.