Mutual Suspicion, Mutual Threats: Getting Japan and South Korea to Work Together


The “2+2” meetings that Secretary of State Antony Blinken and Defense Secretary Lloyd Austin held with their Japanese and South Korean counterparts in March were an encouraging start to President Joe Biden’s efforts to rejuvenate shuttle diplomacy with Tokyo and Seoul. Their meetings were the first step in the Biden administration’s promise to restore dedicated American diplomacy not seen in the region since Park Geun-hye’s downfall in late 2016 led to a deterioration of Japanese-South Korean relations. But despite Blinken’s and Austin’s early diplomatic overtures, it is still too soon to say whether the Biden administration can rebuild Japanese-South Korean relations, which suffer from fundamental strategic tensions that extend far beyond even the two countries’ chronic historical differences. These obstacles notwithstanding, Washington should try to convince Tokyo and Seoul to cooperate on their mutual national security challenges other than that posed by North Korea — so far, the only issue on which the two capitals really cooperate.

From a U.S. perspective, South Korea’s vigorous support for democracy promotion would be ideal, aligning with Biden’s efforts to restore multilateralism and rules-based leadership in Asia. Seoul’s noticeable absence from the Quad, which has begun to assume a more prominent role in confronting China, represents a glaring weakness in Washington’s Indo-Pacific coalition-building efforts. A less ambitious approach to engaging South Korea is more realistic, however, as Seoul continues to wrestle with the strategic contradictions of its economic dependence on China and security partnership with the United States. Moreover, the divide between South Korean political conservatives and progressives over Seoul’s strategic position in Asia, which lies at the heart of its confusion over relations with Tokyo, runs deep.



Reason dictates, therefore, that for the foreseeable future, Biden should not be in the business of forcing South Korea into any dramatic strategic choices between Washington and Beijing. Still, to ensure the Blue House remains an active participant in Biden’s coalition-building efforts, where possible Seoul should work with Tokyo — still its closest security and economic partner aside from the United States and China. Cooperation around a set of low-hanging, incremental, and focused security issues could pave the way toward more considerable forms of alignment later on. Otherwise, Washington will inevitably face recurrent obstacles to addressing both the North Korean nuclear threat and China’s coercive behavior.

The hurdles to closer Japanese-South Korean relations remain formidable and largely outside Washington’s control. Without innovation, U.S. policymakers will remain at an impasse. Instead of urging South Korea to join hands with Japan in a broader confrontational approach toward China, Washington should encourage Seoul to cooperate with Tokyo on specific areas of insecurity.

Recent Developments

As an advanced democratic and free market society, South Korea is a natural — indeed indispensable — partner in Biden’s efforts to mold a “free, open, secure and prosperous Indo-Pacific.” However, as U.S.-Chinese strategic competition mounts, Beijing can be expected to use its economic leverage to entice Seoul, chipping away at what may increasingly become a weak link in the U.S. alliance system in Asia. Accordingly, Biden’s efforts to restore U.S. leadership in Asia, with South Korea firmly at its side, may yet hang in the balance.

Indeed, South Korea features conservatively in a renewed flurry of multilateral initiatives galvanized by the Biden administration’s early response to the challenge from China. Seoul instead has been focused on patching a range of bilateral issues with the United States and continued tensions with Japan.

Not all is bleak in Japanese-South Korean relations, to be sure. Despite their ongoing, highly publicized differences over history — including the issue of South Korean women forced into sexual servitude by the Japanese army during World War II — the two countries’ militaries continue to engage at the working level and participate in regular exercises aimed at enhancing joint operational readiness. Amid their recent differences, the two have continued to take part in various maritime exercises, including Cobra Gold, Pacific Vanguard, Sea Dragon, Pacific Dragon, and RIMPAC. In 2020, President Moon Jae-in’s careful handling of the General Security of Military Intelligence Agreement, an important bilateral military intelligence-sharing pact designed to improve the joint response to North Korea, underscores the long-term feasibility of gradual efforts to carve out a bilateral security agenda without inducing political backlash. If Japan and South Korea approach other common interests similarly, further low-profile attempts at sustained coordination might not be unrealistic.

But even with a properly conceived and executed agenda, the Biden administration will have its work cut out to reduce the current distance between Tokyo and Seoul. Today, security relations between the two countries appear paralyzed, a lingering effect of the various diplomatic hostilities which broke loose in 2018 .The Moon administration withdrew from the 2015 comfort women” agreement, while the relationship of the two U.S. allies deteriorated precipitously with a landmark South Korean Supreme Court ruling in October 2018 on the Japanese industry’s culpability for the use of forced labor before 1945. A disagreement over maritime rules of engagement in late 2018, Tokyo’s export controls on Korean semiconductor inputs, and Seoul’s threats to withdraw from their military intelligence-sharing agreement led to further bilateral animus. Each nation stripped the other of most-favored nation trading status. The World Trade Organization’s dispute settlement body, already enfeebled by nations’ refusal to adhere to international trading standards, became a staging ground for Japanese outrage at South Korea’s restrictions on irradiated seafood from Fukushima.

Following a change in the Japanese administration this past September, South Korean lawmakers prodded Moon to revisit diplomatic options. But Moon’s efforts to signal a renewed commitment to bilateral diplomacy have met with only grudging support among policymakers in Tokyo. Despite multiple recent meetings involving senior officials and lawmakers, the comfort women issue and forced labor legal disputes continue to hinder government attempts at dialogue. Thus, high-level talks have been constrained by domestic politics in both countries, and the two sides remain miles apart on how to break the current stalemate over historical issues. If the South Korean Supreme Court moves to liquidate the holdings of Japanese companies implicated in the wartime use of forced labor, beginning with Nippon Steel — in accordance with the Seoul High Court’s decision in 2013 — public attitudes could boil over, causing bilateral relations to nosedive again.

Mutual Threats

To lower the temperature of Japanese-South Korean relations and yet still make progress on important areas of common interest, Biden’s pro-alliance, Indo-Pacific advisers will need to build momentum around security issues quickly but quietly to prevent further political and diplomatic fallout. We identify three areas of insecurity in particular that both Tokyo and Seoul care deeply about and that, therefore, represent potential low-hanging fruit for a U.S. administration bent on shifting alliance relations in a more constructive direction.

The first area of potential cooperation is protecting freedom of navigation and overflight. Exploiting the current atmosphere of suspicion between Tokyo and Seoul, China and Russia have coordinated multiple intrusions since July 2019 into Japanese and South Korean airspace over the disputed Dokdo/Takeshima islands. Initially foreseen as an annual joint military exercise, the Sino-Russian provocations have developed into a more irregular pattern of behavior mimicking Beijing’s frequent incursions in the South China Sea, East China Sea, and Yellow Sea. These exercises reportedly prompted confusion and additional disagreement between Tokyo and Seoul. Designed to test the two U.S. allies’ ability to coordinate under pressure, these exercises underscore the necessity for both sides to set aside their territorial disagreements and cooperate to protect their overlapping air defense identification zones.

The second proximate area of coordination is establishing supply chain resilience. Though economic statecraft has been an enduring fixture of the Chinese Communist Party’s foreign policy toolkit since the 1970s, Beijing has dramatically weaponized its economic influence over neighbors in the last decade. In 2010, Beijing restricted the export of rare earth minerals used to manufacture Japanese cars and electronics following the collision between a Chinese fishing boat and two Japanese coast guard vessels near the disputed Senkaku islands. As the dispute escalated in 2012, China encouraged nationwide boycotts of Japanese businesses, much as it did in 2005 when its first instinct was to turn a blind eye to anti-Japanese protests following Tokyo’s campaign for permanent membership on the United Nations Security Council. In January, Beijing took new steps that could limit access to its supply of rare earth metals.

In the midst of a trade dispute with South Korea in 2000, Beijing placed import restrictions on over $500 million in Korean cell phones and raw plastics after Seoul slapped a 315 percent tariff on Chinese garlic purchases to protect its domestic farmers. In 2005, Beijing barred imports of Korean cosmetics when Seoul suspended purchases of Chinese kimchi due to health safety concerns. Famously, in 2017, Korean businesses in China hemorrhaged over $15.6 billion when a nationalist backlash erupted after Seoul and Washington jointly deployed the U.S. Terminal High Altitude Area Defense missile defense system.

Emboldened by the U.S. capitalism model’s apparent weakness after the 2008 financial crisis, Beijing has increasingly asserted power beyond its near-abroad. Beijing’s confidence has been further vivified by the American public’s growing uncertainty about — if not its “genuine attitudinal break” with — the Washington establishment’s foreign policy commitments.

Cyber is a third important area of cooperation. Escalating cyber provocations, accelerated by the rapid digital transformation since the COVID-19 outbreak, should also provide incentives for coordination between Tokyo and Seoul. During the escalation of U.S.-North Korean tensions in 2017, Chinese hackers targeted the Japanese defense industry, possibly to learn what Tokyo knew about the Trump administration’s views on the nuclear impasse with Pyongyang. Ahead of the first U.S.-North Korean summit in Singapore in 2018, Chinese and Russian hackers attacked a number of Korean companies. In 2018, a Beijing-affiliated hacker group was the main suspect behind a massive cyber operation against Japanese defense contractor Mitsubishi Electric, and the company weathered another cyber attack this past November. In 2019, South Korea’s Defense Acquisition Program Administration reported that the majority of cyber attacks against it originated from China. Interestingly, no North Korean internet protocol addresses were identified. A similar pattern of most attacks originating from China has been corroborated by Seoul’s science and technology ministry, validating accusations that Beijing is financing and harboring North Korean threat actors.

In 2020, Chinese actors continued to target South Korean government and private entities including mass media, energy companies, and the foreign ministry, which alone withstood more than a thousand attacks. Similarly, CrowdStrike’s latest global cyber security survey found that various unidentified hackers, including some likely from China and North Korea, penetrated over a hundred major Japanese companies across various critical sectors last year. China and North Korea have infiltrated Japanese and South Korean research institutions and pharmaceutical companies developing COVID-19 vaccines. Russia is believed to have engineered the same type of attacks. A joint U.S.-British intelligence operation uncovered Russian plans to attack the Tokyo Olympics. In June, North Korean hackers sent COVID-19-themed phishing emails to over five million businesses and individuals in six countries including Japan and South Korea. Recently, Japan’s Nuclear Regulation Authority was compromised by suspected North Korean hackers. According to U.S. cyber authorities, Pyongyang has also conducted a broad cyber espionage campaign against policy experts, think tanks, and government agencies in South Korea, Japan, and the United States.

Formalizing Limited Military Cooperation

Thus, despite recent Japanese-South Korean tensions and the historically fraught nature of their relationship, geopolitical conditions are ripe for some future bilateral security coordination. With their intelligence-sharing pact renewed for a fourth consecutive year in 2020, Tokyo and Seoul should move to contemplate new joint strategies for addressing their shared challenges. A formal bilateral agreement to help each other out with military logistics, which the two countries have repeatedly tried and failed to negotiate, may be within reach now.

One such initiative could be a bilateral acquisition and cross-servicing agreement. Also known as a mutual support agreement, the first such pact was enacted in 1979 by NATO to facilitate exchanges of logistics support, supplies, and services. In general, these cross-servicing agreements authorize the loan or lease of military equipment for multilateral peacekeeping and other humanitarian operations. The agreement does not commit a signatory to military action, Rather, it denotes an expression of mutual support in case a logistics need should arise. Previously, the absence of a logistics agreement between Japan and South Korea induced massive political scandal in and between Seoul and Tokyo over cooperating even on an initiative as sensible and constructive as peacekeeping in South Sudan. Ideally, a Japanese-South Korean pact would diminish logistics burdens and increase on-site interoperability, thereby enhancing joint operational readiness and cost-effectiveness.

Japan and South Korea maintain acquisition and cross-servicing agreements with six and 15 countries, respectively, yet multiple attempts to reach their own agreement have failed. A bilateral logistics agreement would solidify the two countries’ ability to respond jointly to emerging maritime, air, and potentially cyber contingencies. Such an agreement would build on established forms of bilateral cooperation, including exercises and military exchanges, while supporting U.S. and Japanese efforts to enhance “minilateral” cooperation among allies in Asia. It would also help the Japanese and South Korean governments strengthen military capacity, thus lowering their reliance on the United States. In time, improved contingency planning and execution might help rebuild bilateral trust and confidence. This could engender new political opportunities for further security cooperation.

Two Views on China and Other Threats

Further Japanese-South Korean alignment on unconventional threats cannot be neglected if Biden is to succeed in renovating U.S. alliances in anticipation of great-power competition. Yet, Washington should be clear-eyed about what is possible between Tokyo and Seoul.

For one, Tokyo and Seoul are not in complete lockstep about the best response to new contingencies. While Japan’s experience with Chinese economic retaliation was initially traumatic, the Japanese political establishment’s reaction quickly became one of hardened determination to preserve its economic sovereignty. Within months of China’s 2010 rare earth import restrictions, Tokyo brokered a long-term supply deal with Australia and by 2017, had diversified 30 percent of its rare earth demand from Chinese suppliers. Between 2013 and 2016, the value of Japanese foreign investment to China plummeted by roughly 50 percent and today, nearly 70 percent of major Japanese companies in China believe doing business there is risky.

South Korea’s missile defense dispute with China in 2017, on the other hand, did not immediately result in economic security reforms; rather, Seoul has since resisted being hamstrung into any decision that might risk offending Beijing. Moreover, it was Japan’s restrictions on exports of semiconductor inputs to South Korea in 2019, not China’s substantially greater coercion over the joint decision of the U.S.-South Korean alliance to deploy a missile defense system to South Korea, that eventually prompted Seoul to consider new investments to reduce its dependency on foreign technologies.

Similarly, Japan and South Korea are not aligned in their concern about technological leakage. Though both countries remain hesitant to step on the toes of their largest trading partner, the Japanese government has been more willing, at the very least, than the Korean government to take action against Chinese state-affiliated companies in key sectors that compromise its national security or the privacy of its citizens. Following Washington’s initiative, Japan blacklisted Chinese telecommunications companies Huawei and ZTE from its 5G procurement process. In November 2019, Japan’s National Security Council established a dedicated economic affairs staff to counter Chinese and North Korean intellectual property violations. Around the same time, Japan ratified a bill strengthening its foreign investment rules in an effort to match Washington’s recent Committee on Foreign Investment in the United States reforms. To be sure, the Japanese business community has demurred from decoupling with China, notwithstanding governmental incentives. Indeed, Japanese as well as Korean semiconductor parts suppliers face significant pressure from recent U.S. sanctions against Huawei, one of their a major clients, and have in certain cases applied for exemptions from the ban. Though South Korea also updated its foreign investment rules, Seoul has been loath to divest from the Chinese market. In October, the United States requested South Korea join its Clean Network initiative, focused on building secure telecommunications. Washington praised Korean telecommunications providers SK Telecom and KT as “clean carriers” for shunning Huawei, while criticizing rival LG Uplus for not doing the same. Still, the Moon administration adhered to its existing position not to intervene in company decision-making, ostensibly for legal reasons. Seoul may soon have to reconsider its position. The 2021 National Defense Authorization Act includes a provision to reconsider deploying U.S. troops to countries that use equipment from Huawei and ZTE, raising the stakes for U.S. allies that benefit from Chinese-manufactured technology.

Finally, on cyber, Japan seems fairly ahead of South Korea in its formal cyber security planning and processes. The 2017 WannaCry ransomware attack by North Korea spurred Japan to expedite a new national cyber security strategy the following year, building on its previous two cyber blueprints in 2013 and 2015. Japan’s latest National Defense Program Guidelines in 2018 highlighted the importance of cyber warfare capabilities, and its National Security Council’s economic security division has made cyber security a priority. Today, the Japanese government confers regularly with operators of critical infrastructure to discuss cyber strategy, and data protection and privacy feature prominently in all of the government’s foreign procurement guidelines. South Korea, meanwhile, only began to push forward with its first cyber strategy in 2019.

A related problem is that the two countries are developing separate policies for securing infrastructure and data — but appear to rarely, if ever, cooperate. The United States, as the common ally, can play an important convenor role in facilitating Japanese-South Korean cyber security cooperation by building on its existing bilateral cyber arrangements with both countries. Indeed, Seoul’s 2016 defense white paper hinted at the need for trilateral coordination on cyber. The U.S. private sector also has a function to fulfill. Public-private teaming on cyber is a necessary cornerstone for protecting privately owned critical infrastructure. Companies like Microsoft, which built a network of cyber crime centers in six Asian cities including Tokyo and Seoul, are at the forefront of regional cyber policy development. Japan and South Korea separately are developing government-military-industry cyber response task forces modeled after established mechanisms in the United States. However, the South Korean National Intelligence Service’s continued reluctance to cooperate with the private sector highlights potential inconsistencies among Seoul’s cyber planners. Japan, the United States, and members of the European Union and the Association of Southeast Asian Nations held virtual joint cyber exercises last month — their third since 2018. Inviting South Korea to such multilateral cyber security fora would help align Seoul’s cyber policies with those of other U.S. allies and like-minded partners.

More Cooperation Is Possible

Despite Japan and South Korea’s 55-year relationship, past bilateral security cooperation has remained limited to dealing with North Korea. Debates in South Korea over military intelligence sharing, logistics exchanges, cyber cooperation, and other security relations with Japan are contentious. As evident from the discordant Japanese-South Korean reaction to recent Sino-Russian airspace intrusions, there is no concrete joint strategy for responding to new threats. Acquisition and cross-servicing agreement talks have progressed intermittently since the late 1990s and, accordingly, remain a difficult undertaking for the foreseeable future. Cooperation on supply chain resilience, while logical, has not yet materialized either. Other security initiatives are also a tall order, though not unachievable with the proper push.

Mutual concern about Beijing’s assertiveness, however, may provide just the necessary incentive to revitalize Japanese-South Korean security cooperation. In Japan, public favorability toward China reached near-record lows in 2020. The Asian Institute for Policy Studies found in 2017, at the height of the U.S. missile defense system controversy, that South Koreans’ views of China were more negative than their views of Japan. Today, anti-Chinese sentiments in South Korea remain as strong as ever. The Moon administration’s outreach to Beijing, while persistent and continuing, has been blunted by public and lawmakers’ concern.

Others have already argued that the Biden presidency’s promise of rejuvenated coalition-building creates a window of opportunity to bolster U.S.-Japanese-South Korean trilateral cooperation. To be sure, while the new administration attempts to turn back the clock on Trump’s more impolitic approach to his Japanese and Korean counterparts, there is no easy solution for restoring regional allied security cooperation. Even attending to such mutually significant issues as maritime sovereignty, supply chain resilience, and cyber security won’t fully inoculate the trilateral relationship against further setbacks and inaction due to Tokyo’s and Seoul’s bilateral shortcomings. But the United States cannot wait for the headwinds of Japanese-South Korean tensions to subside. The Biden administration needs to show immediate and innovative leadership and take advantage of the strong undercurrent of bipartisanship among Democrats and Republicans regarding a proactive U.S. posture in the Indo-Pacific. Biden’s leadership during a moment of considerable strategic peril for Japan and South Korea heralds an opportunity to expand cooperation in new security domains.



Andrew I. Park is president of the Sejong Society of Washington, D.C., a consultant at the Center for Strategic and International Studies , and a US-Japan-Korea working group Emerging Leader at the National Committee on American Foreign Policy. He previously served as an interpreter/translator at the U.S.-ROK Combined Forces Command in Seoul, South Korea, and worked as a researcher at the Embassy of the Republic of Korea. 

Elliot Silverberg is a fellow at Georgetown Universitys Institute for the Study of Diplomacy and a nonresident James Kelly Fellow in Korea studies at the Pacific Forum in Hawaii. He previously worked in consulting and think tanks across Washington, D.C. and Tokyo, Japan.

Image: Twitter (Photo by the National Security Council)