Allies Should Include Japan in Korean Unification Plans

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Allies Should Include Japan in Korean Unification Plans

September 28, 2015 16 min read Download Report
Bruce Klingner
Senior Research Fellow, Northeast Asia
Bruce Klingner specializes in Korean and Japanese affairs as the Senior Research Fellow for Northeast Asia.

South Korean President Park Geun-hye has made Korean unification a central tenet of her foreign policy strategy. While concurrently pledging to respond sternly to any North Korean provocation, she has repeatedly tried to engage Pyongyang. Like previous South Korean presidents, Park has sought dialogue with Pyongyang to defuse tensions, deter North Korean attacks, and improve bilateral relations. But more so than her predecessors, she has made reunification a tangible short-term, rather than esoteric long-term, objective.

North Korea has characteristically rejected unification discussion, but Park persists in advocating reconciliation. Park’s efforts may be largely directed at her domestic constituency since a declining percentage of South Koreans favor unifying with their recalcitrant brethren to the north. Park’s declaration that unification would provide a “jackpot”[1] or “bonanza”[2] for South Korea’s economy was largely directed at her country’s young generation, which polls show is the least supportive of unification.

Despite her advocacy and creation of a presidential task force on unification, Park has not articulated a clear vision of how she would achieve or pay for it. Extensive internal government planning is likely underway. That said, one aspect that has never been discussed publicly and may be overlooked in official preparations is the necessity to involve Japan in Korean unification plans.

Japanese involvement would be extremely controversial to the South Korean populace given strong national animus due to Japan’s brutal 1910–1945 occupation of the Korean Peninsula. Bilateral tensions over historical issues are cyclical, but are perhaps at their greatest nadir due to Korean concerns over Prime Minister Shinzo Abe’s perceived revisionist views and intent to alter Japan’s security posture.

However, both President Park and Prime Minister Abe have made efforts in recent months to improve relations, including resuming meetings between financial, security, and foreign policy officials. Abe’s better-than-expected statement commemorating the 70th anniversary of the end of World War II and Park’s pragmatic response provide further impetus for bilateral planning.

Initial bilateral efforts should prioritize improving allied deterrence and defense against the North Korean security threat. However, multilateral planning among South Korea, the U.S., and Japan on Korean unification would facilitate long-term plans and highlight common objectives, particularly between Seoul and Tokyo. President Park and Prime Minister Abe should embrace joint efforts on achieving Korean unification as mutually beneficial, including further reducing bilateral tensions.

Defining the Unified Korean End State

Korean reunification quite simply requires the absorption of North Korea by South Korea. Nothing of the North Korean regime should be saved, except the people. South Koreans should not be expected to give up any of their political or economic rights to accommodate any aspect of the North Korean regime.

Such an approach is consistent with Article 4 of the South Korean constitution: “The Republic of Korea seeks unification and formulates and carries out a policy of peaceful unification based on the principles of freedom and democracy.”[3] Neither of these principles exists in North Korea, nor do free-market principles, respect for the rule of law, or respect for human rights—all of which are characteristics of South Korean society.

Therefore, unification should not be a quest to integrate or average the two systems. That would be neither desirable nor possible. For example, North Korean and South Korean human rights policies cannot be averaged. The same is true for a unified Korean political and economic system. The remnants of the North Korean dictatorship and state-directed economy cannot be accommodated in the existing South Korean system of freedom and democracy.

North Korea Resists Unification

Pyongyang instead advocates creating a confederated “one Korea, two systems” as an interim step. But doing so would retain heinous aspects of the regime while opening Seoul to pressure to lower its defenses, such as altering its alliance with the United States or prematurely signing a peace treaty before reducing the North Korean military threat.

North Korea resists President Park’s trustpolitik policy since the regime fears opening its economy and political system to what it perceives as the contagion of outside influence. Pyongyang rejected President Park’s Dresden Declaration, declaring Seoul should stop “prattling on and dreaming about” unrealistic unification proposals. The regime derided Park as “dreaming a foolish dream of achieving unification through absorption [and] her harangue about support for the North’s economic development is so ridiculous as to make even a cat laugh.”[4]

Kim Jong-un’s New Year’s Day speeches and other North Korean statements show an emphasis on maintaining current policy without even a hint of economic reform. Frustrated by foreign speculation of reform, Pyongyang even denounced such suggestions as “the height of ignorance. To expect policy change and reform and opening from [North Korea] is nothing but a foolish and silly dream…. There cannot be any slightest change in all policies.”[5]

North Korea is therefore the greatest impediment to Korean unification, not resistance by Korea’s neighbors, as some in the South insist. Kim Jong-un has demonstrated that he is as resistant to reform and moderating North Korea’s belligerent foreign policy as his predecessors were.

Would Japan Assist Korean Unification?

Given severe strains in the Japanese–South Korean relationship, Koreans often presume that Japan does not support or would even seek to obstruct reunification of the Korean Peninsula. The predominantly cited reason is that Japan would not want a stronger unified Korean challenger to its economy.

Assessing Japanese views on Korean unification is highly speculative given the few Japanese government statements, limited academic work done in recent years, and little or no official discussion between Seoul and Tokyo on the topic.

Previous academic studies occurred mostly during times of better Japanese–Korean relations with commensurate higher expectations that both countries were willing to work together on security issues, including unification. Recent discussions between the South Korean and Japanese governments have been subsumed by a focus on the past, rather than on the present or future.

The relatively few Japanese official statements on Korean unification have been supportive, albeit terse. Recently, Japanese views toward Korean unification have become more positive due to increasingly belligerent North Korean behavior, Pyongyang’s growing nuclear and missile capabilities, and the realization that Kim Jong-un is just as dangerous and resistant to reform as his predecessors.

Korean Unification Would Benefit Japan

As long as the Korean Peninsula remains divided and the North Korean threat remains, Japan pays an enormous opportunity cost. For years, Tokyo has devoted considerable funds to deploy a ballistic missile defense system. Japan supports the presence of U.S. military forces in its country both monetarily and at the risk of North Korean threats of nuclear attack.

Japan has borne these costs both for its own national interests and to support the U.S. ability to defend South Korea. Korean unification could reduce some of these costs. Japan would enjoy significant security and economic benefits from Korean unification since it would improve peace, security, and prosperity for Northeast Asia. Even though Tokyo will need to maintain a robust defensive force against increasing Chinese incursions, the removal of North Korea’s nuclear and missile forces would eliminate the most immediate and serious security threat to Japan.

Korean unification would also dramatically improve the potential for resolving the abductee issue, a key foreign policy objective of the Japanese government and populace. While a unified Korea could eventually become a stronger economic competitor, Korean unification could conversely be seen as providing a larger Korean market and creating opportunities for Japanese businesses. Japanese firms would likely be “among those involved in developing the North’s dilapidated infrastructure, and its manufacturers and retailers could profit in the long run from an expanded Korean export market.”[6]

A strong and unified Korea could even help to “balance against growing Chinese power in Northeast Asia, even if Seoul still maintains some distance from Tokyo—an outcome which will be more likely if Japan is seen to have aided Korea at a time of need, while China is believed to have undermined its aspirations.”[7]

Tokyo has a huge stake in the manner in which a unified Korea takes place because it will affect Japan’s economy, national security, military posture, and relations with its neighbors as well as with the United States.

Unification Is Not on Japan’s Radar

Yet even though Korean unification is “so critical to its future, Japan is unlikely to play a proactive or assertive role on Korean issues. Rather, it is more likely to be cautious, reactive, and adaptive to the process of unification as it develops.”[8]

Japan will likely take a “generally reactive and adaptive stance toward the process because it is ambivalent about reunification and because it labors under constraints imposed by its long abstention from security commitments, its historically strained relations with Korea, and its complex relations with China.”[9]

Japan operates under a number of constraints, including a deliberative consensus-building policymaking process, insular security policy, constitutional constraints on its security forces, an inexhaustible ability to delay decisions and actions, the legacy of its 20th-century actions, and intense South Korean suspicion. Overall, Tokyo does not see Korean unification as a pressing issue for Japan and is instead focused on growing North Korean and Chinese security threats.

Japan Would Play an Important Unification Role

South Korea should play the predominant role in determining the course and pace of Korean unification. The United States would continue to serve as South Korea’s protector, ensuring Seoul’s security and national interests. Tokyo would play a secondary and reactive role in Korean unification. However, Japan’s importance should not be underestimated since its participation would be critical both in the military operations likely to precede Korean unification and in potentially providing extensive economic support after Korean unification.

Japan provides a critical base of support for U.S. forces defending South Korea during a conflict with Pyongyang. Seven U.S. bases in Japan are designated as part of the United Nations Command Rear, which maintains the status of forces agreement for U.N. forces in Japan during peacetime and would serve as a staging area during a Korean crisis.

U.S. military forces would need access to additional Japanese bases for strike and logistics operations. U.S. Marine Corps units on Okinawa are essential to allied security plans for responding to full-scale invasion by North Korean forces as well as to other military contingencies.

Japanese Self-Defense Forces could participate in important combat support roles, such as minesweeping to maintain sea lines of communication with the United States and the Korean Peninsula. Quite simply, the United States cannot defend South Korea without Japan, a point seemingly lost on the South Korean government and populace.

North Korea understands the importance of Japanese participation in military contingency plans and has sought to prevent it. In March 2013, the Korean People’s Army Supreme Command threatened, “The US should not forget that Anderson AFB in Guam [and] naval bases in Japan and Okinawa are within striking range of the DPRK’s precision strike means.”[10] On October 10, 2012, the North Korean National Defense Commission warned that its strategic rocket forces could hit the mainland U.S. and U.S. bases in South Korea, Japan, and Guam.[11]

Japan Could Help Pay for Unification

Estimates of the cost of stabilizing and rebuilding northern Korea after reunification vary greatly, although most studies estimate a requirement of several trillion dollars. Korea clearly cannot bear the entire financial burden by itself.

Seoul could impose additional taxes on its populace or seek outside assistance from foreign governments, financial institutions, and nongovernmental organizations. Korea could also turn to the United States, China, the European Union, U.N. agencies, and the Asian Development Bank and Asian Infrastructure Investment Bank.

Japan would be an obvious potential donor since it consistently ranks as one of the world’s most generous aid providers. When Japan formalized diplomatic relations with South Korea in 1965, Tokyo provided $600 million to $800 million in development aid, which was seen by some as unofficial reparations for its occupation of the Korean Peninsula during 1910–1945.

If Japan were to normalize relations with North Korea, some predict that Tokyo could provide $10 billion (the 1965 payment adjusted for inflation). However, it is uncertain whether Japan would feel bound to provide such a payment following Korean unification. Nor is it clear whether any Japanese contribution would be a “no strings attached” donation, a loan to the Korean government, or investment in business projects with expectations for profits.

Japanese Concerns over Unification

Although Japan is not philosophically opposed to Korean unification, it has concerns over the manner in which unification is accomplished and the parameters of the end state. Japan would want a unified Korea that retains South Korea’s principles of freedom, democracy, free markets, rule of law, and respect for human rights.

Japan has a strong trading and economic relationship with South Korea that it would not want to see change. Sharing these “basic values with a unified Korea will help to maintain long-term stable bilateral relations, to address frictions and disputes between the two countries in a practical and controlled manner, and to further build confidence and trust between the two countries.”[12]

Tokyo would also seek a unified Korea that does not pose a security threat, pursue nationalist hostility toward Japan, or significantly shift its foreign and security policy stance away from the United States in favor of closer relations with China.

Of primary importance to Japan would be the unified Korea’s security policy after absorbing North Korea. The initial indicator would be whether Korea quickly announces that it will destroy the North Korean nuclear arsenal and dispose of all nuclear weapons production programs under close international verification.

The initial dismantlement and long-term monitoring of compliance would be expected to comply with Non-Proliferation Treaty and International Atomic Energy Agency standards. If unified Korea retained North Korea’s nuclear arsenal, it could lead Tokyo to develop its own nuclear weapons program.

Japan would also not want to see a unified Korea develop offensive weapons that could threaten Japan, such as medium-range ballistic missiles and long-range bombers, or expand its naval capability and activities without coordinating with the United States.[13] Tokyo would want unified Korea to remain aligned with the United States with some residual, although possibly reduced, U.S. military presence on the Korean Peninsula. Although the North Korean threat would have been eliminated, Tokyo would still be worried about China.

Tokyo sees the U.S.–South Korean alliance as a critical component of its own security, and elimination of U.S. Forces Korea (USFK) would put great pressure for a reduction or removal of U.S. Forces Japan (USFJ). This pressure could come from the Japanese public as well as from the American public and the U.S. Congress. Japan might also seek, although never publicly articulate, USFK as a hedge against future Korean ambitions.

While most assume that a unified Korea would maintain an alliance with the United States and not alter its foreign policy and security posture, alternative scenarios are possible. A unified Korea could change its strategic focus to side more with China or choose to become more independent, both of which would be seen as a serious threat to Japanese national security.

A unified Korea could become even more nationalistic and susceptible to Chinese entreaties, particularly if Tokyo was perceived as resistant to Korean unification. There is already trepidation that Seoul is becoming overly close with Beijing. During their summit meetings, Presidents Xi Jinping and Park Geun-hye played up common historical grievances with Japan, ignoring Beijing’s role in fighting against South Korea in the Korean War.

Tokyo is particularly concerned about a Korean shift toward China since Japan has become more wary of U.S. commitment to Japan’s defense. Japanese policymakers point to drastic cuts in the U.S. defense budget and perceptions of dwindling American resolve under the Obama Administration. Japanese trepidation on these two issues could lead Tokyo to increase its military forces and security role, perhaps more independently of the United States.

South Korea would likely be dismissive of such Japanese concerns, but Seoul has not yet articulated its vision of a unified Korea. This reticence is worrisome and could fuel Japanese and U.S. anxieties over Korean intentions. For all of the Park Administration’s focus on unification, it has not defined the characteristics and foreign and security policies of a unified Korea.

The lack of detail may be because the Park Administration is still working through details or because publicly defining the parameters of a unified Korea would make all too clear to Pyongyang that it means the absorption of the North. As such, South Korean articulation of the Korean end state would stiffen regime resistance to Park’s trustpolitik and engagement efforts.

Just as Korea wants Japanese reassurances and transparency on collective self-defense—which Tokyo has repeatedly provided—Japan will want reciprocal measures from Korea on unification.

Unification Support Could Be Conditional

Given these concerns, Japanese support for unification would depend heavily on the manner of unification, the status of bilateral relations with Seoul at the time, and the foreign and security policies of a unified Korea. Japanese economic support after unification would depend on whether Tokyo perceived that the status quo was shifting against its national interests.

In pre-unification scenarios involving security operations, the Japanese involvement is not guaranteed, particularly since the government would need to convince the Japanese public that Japanese involvement was in the national interest, even in the face of North Korean nuclear threats.

For example, Japanese and U.S. officials have contradictory views on whether prior Japanese approval is required to use U.S. forces in Japan for Korean contingencies. In July 2014, Prime Minister Abe told the Diet that “U.S. Marines cannot rush without first engaging in prior consultation with Japan. Unless Japan allows it, it cannot leave Japan to help Korea.” However, the U.S. State Department affirmed in November 2014 that Washington would automatically deploy American forces in Japan without prior consultations with Tokyo in the case of North Korean provocation or an emergency on the peninsula.[14]

Japanese officials have privately commented that, given the current state of strained relations with South Korea, Tokyo may not be inclined to provide either security or economic assistance to Korea during a crisis. The Japanese government could have more difficulty convincing the Japanese public to support a policy of defying North Korean nuclear threats to provide assistance to Seoul.

South Korea should be less concerned that Japan will be overeager to become involved—the oft-quoted fear of “Japanese boots again on the Korean Peninsula”—and instead worry that Japan would be reluctant, resistant, or refuse to become involved. Just as South Korean public opinion polls show strongly negative views of Japan, the reverse is also true.

Japan Needs to Be Wooed

Both Seoul and Washington need to realize that Tokyo needs to be persuaded to ensure its involvement. It behooves Seoul to improve relations with Tokyo for its own unification interests. Both South Korea and Japan need to reassure each other that neither poses a security threat to the other. A critical first step to earning Japanese support is for Seoul to be more forthright and transparent in articulating its vision of a unified Korea, particularly its foreign and security policies.

This should be part of a renewed effort by both Tokyo and Seoul to begin a reconciliation process to resolve difficult historical issues. Currently strained relations between the two democracies not only undermine common security interests, but also could hinder Korean unification.

Reconciling will not be easy given the legacy of mistrust and paranoia between them. Washington should continue to play the role of behind-the-scenes facilitator. The U.S. alliances and presence of American forces in South Korea and Japan should provide security reassurances to both countries.

What Should Be Done

South Korea, Japan, and the United States need to prepare for Korean unification:

  • Further study of Korean unification by South Korean, Japanese, and U.S. scholars and government officials is needed given its unavoidable impact on all three countries. Although many excellent studies were conducted in the past, they may be outdated given the changing security in Northeast Asia and renewed tensions between Seoul and Tokyo.
  • South Korea, Japan, and the United States should engage in extensive trilateral whole-of-government preparations for Korean unification. Military preparations are likely more fully developed than the diplomatic, economic, legal, and aid components. Although Seoul should drive the unification effort, Washington and Tokyo need to be on board early in the process to facilitate coordinated efforts and generate national support.
  • Washington, Seoul, and Tokyo should create a Trilateral Security Initiative (2+2+2 meeting) with an annual meeting of foreign and defense ministers to develop joint strategies for addressing common threats and objectives. The initiative should focus on developing trilateral plans for responding to North Korean provocations as well as a strategy for Korean unification, including aid and development contributions. The South Korean Minister of Unification could attend in addition to or in lieu of the foreign minister.
  • Even now, Seoul should reach out to Tokyo and Washington to explain its vision of the nature and policies of a unified Korea. The key to reducing Japanese suspicions and preventing a potential security dilemma over unification is to initiate and maintain as much dialogue and transparency as possible. An important first step would be for Seoul to declare that a unified Korea would not retain any nuclear weapons or means to produce them.
  • Japan should declare its support for Korean unification and pledge to contribute to a Korean unification fund. Such a pledge could positively influence the Korean people’s perception of Japan.
  • Japan should work with South Korea to establish a framework for resolving contentious historical and sovereignty issues. Both countries should refrain from prioritizing historical issues over addressing present and future security issues.
  • The three countries should increase bilateral South Korea–Japan and trilateral South Korea–Japan–U.S. military exercises and maritime security. The approval in December 2014 of a limited trilateral General Security of Military Information Agreement was a commendable first step, but more extensive coordination is necessary.


Despite the Park Administration’s focus on Korean unification, much work remains to prepare the way. One vital component is improving South Korean relations with Japan. Improving relations is in South Korean national interests because it would augment defense against the North Korean threat as well as facilitate eventual Korean unification.

Japanese–South Korean rapprochement has a viable path forward, but it will not be easy. It will require both Abe and Park to show strong and bold leadership by standing up to the fervent nationalist elements in their countries that have worked against reconciliation. Hopefully, both leaders are willing to do so.

The way ahead is murky and fraught with danger. Yet unification is the only way to reunite the Korean people. Someday, all Koreans in both north and south will be able to walk freely across a nation no longer divided by trenches, barbed wire, and barriers of distrust—a Korea united by common bonds of culture and democracy and freedom. To achieve that goal, South Korea should work with the United States as well as Japan.

—Bruce Klingner is Senior Research Fellow for Northeast Asia in the Asian Studies Center, of the Kathryn and Shelby Cullom Davis Institute for National Security and Foreign Policy, at The Heritage Foundation.

[1] Seo Ji-eun, “Unification May Be Jackpot: Park,” Korea JoongAng Daily, January 7, 2014, (accessed September 12, 2015).

[2] Kang Seung-woo, “Park Stresses Unification Roadmap,” The Korea Times, February 16, 2015, (accessed September 12, 2015).

[3] Constitution of the Republic of Korea, art. 4, (accessed September 8, 2015) (emphasis added).

[4] Korean Central News Agency, “DPRK Slams Park Geun-hye’s Reckless Remarks,” September 26, 2014.

[5] BBC News, “North Korea Dismisses South’s Talk of Reform,” July 29, 2012, (accessed September 8, 2015).

[6] Meredith Shaw and Taylor Washburn, “East Asia’s Ultimate Geopolitical Puzzle: Korean Unification,” The National Interest, June 13, 2014, (accessed September 8, 2015).

[7] Ibid.

[8] Michael H. Armacost and Kenneth B. Pyle, “Japan and the Unification of Korea: Challenges for U.S. Policy Coordination,” National Bureau of Asian Research, March 1999, p. 21, (accessed September 8, 2015).

[9] Ibid., p. 5.

[10] “North Korea Says U.S. Bases in Japan, Guam Could Be Targeted by Nukes,” Mainichi Shimbun, March 21, 2013.

[11] “North Korea Says Its Rockets Could Hit Continental US,” Chosun Ilbo, October 12, 2012.

[12] Hideki Yamaji, “Policy Recommendations for Japan: Unification of the Korean Peninsula,” The Brookings Institution, July 2004, p. 5, (accessed September 8, 2015).

[13] Ibid.

[14] “Washington: Prior Talks with Tokyo Not Needed for US Military Dispatch to Korea,” Dong-a Ilbo, November 18, 2014, (accessed September 8, 2015)


Bruce Klingner
Bruce Klingner

Senior Research Fellow, Northeast Asia