Bringing Japan and South Korea together as U.S. security partners

Earlier this week, Secretary of Defense Lloyd Austin and his ministerial counterparts, Kiharu Minoru of Japan and Shin Won-Sik of South Korea, jointly announced a new agreement titled, in rather wordy fashion, “Memorandum of Cooperation on the Trilateral Security Cooperation Framework.”

The agreement represents yet another major step in realizing Washington’s long-standing goal to secure a closer security relationship between America’s two powerful East Asian allies, Japan and South Korea.

The announcement focuses on the threat from North Korea, and in that regard includes a reference to the ministers’ “grave concern over the increasing military and economic cooperation commitment between the Russian Federation and [North Korea].”

On the other hand, the release makes no mention of China and only indirectly alludes to the threat it poses. All the three ministers were prepared to publicize was that “they shared assessments of recent maritime and air military activities in the Indo-Pacific region, including the South China Sea…they strongly oppose any unilateral attempts to change the status quo in the waters of the Indo-Pacific…[and they] stressed the importance of fully respecting international law, including freedom of navigation and overflight.”

The reluctance of the three parties explicitly to call out China’s behavior contrasts sharply with the language that appears in the report of the congressionally mandated Commission on the National Defense Strategy. That report appeared one day after the agreement was announced. Although it “strongly praises U.S. diplomatic and defense efforts to strengthen partnerships in Asia,” it states that these efforts are “driven in response to Chinese provocations.” 

That the ministers did not go as far as the commission report reflects an ongoing divergence of views among them regarding relations with Beijing. Washington has taken a tough stance against China, one that has bipartisan domestic support. Although Tokyo and Seoul likewise have come to regard China as a major security threat, China (including Hong Kong) is the leading export market for both Japan and South Korea. Not surprisingly, they are somewhat reticent about following Washington’s lead in explicitly singling out Beijing as the major threat they both know it to be.

Despite their military cooperation, and despite Tokyo’s formal apology for the treatment of South Korean “comfort women,” the two nations have yet to resolve their differences over the history of the 35 years (1910-1945) when South Korea was under Japanese control. Indeed, the history of Japanese domination over Korea extends at least as far back as 1876, when Tokyo forced Korea to sign the Treaty of Kanghwa, which opened Korean ports to Japanese ships and, more importantly, forced Korea to pull out of its tributary relationship with China. 

It is therefore not surprising that while polls taken in late 2023 show the Japanese public to have a more favorable view of South Korea, South Korean public attitudes have not changed, despite the government’s efforts to improve relations with Japan. Moreover, not all Koreans see China as a security threat. 

It is also worth recalling that in December 2015, Seoul and Tokyo reached an understanding that was meant to settle the comfort women issue “finally and irreversibly.” Japan apologized and committed to pay some $8 million to victims. Four years later, Seoul effectively nullified the agreement, in part due to public demands that Japanese companies had exploited the women, and that they, not just the government, must provide compensation to the victims. Indeed, in November 2023 the High Court in Seoul rejected Japanese claims of sovereign immunity and upheld the right of the women to sue the Japanese government; in January, the court ordered Japanese companies to compensate the women. 

Given ongoing public hostility toward Japan — there are those who still consider Japan a more dangerous enemy than North Korea — and the politically-driven fluctuations in relations with both the U.S. and Japan depending on which Korean party is in power, there is no guarantee that the new security agreement would survive a future change of government in Seoul.

Perhaps the best way to solidify the current three-way cooperation in the security sphere is for Washington to press for closer ties between Seoul and Tokyo in areas other than the military. This would call for a true whole-of-government effort, what the Biden administration has termed “integrated deterrence.”

Yet as the National Defense Strategy Commission has pointed out, “recent administrations of both political parties have not pursued a comprehensive approach to national security.” In particular, the commission report notes that “there is no coordinated U.S. economic agenda for the Indo-Pacific to accompany the military strategy.” The report adds, only by having “an interagency planning process that complements military operation plans with diplomatic, economic, and communications tools in conjunction with allies and partners,” can integrated deterrence truly succeed.

Surely these observations offer a prescription for both overcoming the mutual suspicion that both populations, especially in South Korean, still harbor. Only when that suspicion is fully overcome can the security partnership among the three allies endure, regardless of whatever future governmental changes in any or all of them might bring.

Dov S. Zakheim is a senior adviser at the Center for Strategic and International Studies and vice chairman of the board for the Foreign Policy Research Institute. He was undersecretary of Defense (comptroller) and chief financial officer for the Department of Defense from 2001 to 2004 and a deputy undersecretary of Defense from 1985 to 1987.