It is a singular honor and privilege to have the opportunity to address the annual conference of The Asan Institute for Policy Studies today, one of the Republic of Korea’s foremost think tanks, distinguished by its profound expertise in security policy.

On the theme before us today, “Modernizing Alliances,” I would like to offer my reflections on why such modernization has become necessary at this juncture, what form it should take, and what questions Japan and the Republic of Korea must debate—and ultimately resolve—both domestically and in our external affairs. It is my hope that we may reflect on these questions together.

Five Key Security Questions

1)    Deterrence vis-à-vis North Korea

From the standpoint of preserving the integrity of the Treaty on the Non-Proliferation of Nuclear Weapons, or the NPT regime, the Government of Japan does not recognize North Korea as a nuclear-weapon state. There can be no doubt, however, that North Korea is steadily advancing both its nuclear weapons program and the means of delivering those weapons.

Nuclear deterrence is not the ability to win a nuclear war. It is the ability to convince the adversary that aggression would invite damage so intolerable as to be beyond endurance. If North Korea were to acquire capabilities sufficient to make us believe that it could inflict precisely such unacceptable damage, how should our alliances respond? We in democratic nations, charged with protecting the lives and safety of our citizens, can scarcely be expected to tolerate even a single failure to intercept a nuclear missile aimed at our territory if that failure were to bring catastrophic devastation. At a time when North Korea is markedly enhancing both its capacity for saturation attacks and its ability to launch missiles at high speed along irregular trajectories, this is an urgent and most grave challenge.

To begin with, there is no managed framework of mutual deterrence between the United States and North Korea comparable to the U.S.–Soviet system of mutual assured destruction. Kim Jong Il, the former General Secretary, is said to have once remarked that “there is no need for a world in which North Korea does not exist.” One must therefore ask whether punitive and retaliatory deterrence can ever function with complete reliability against a state whose supreme objective appears to be the preservation of the regime itself. This makes it all the more imperative that we strengthen missile defense so that, even in the event of a nuclear strike, damage may be prevented or, at the very least, minimized, and that we expand shelter infrastructure.

To maximize both deterrence by punishment and deterrence by denial, cooperation among Japan, the United States, and the Republic of Korea—trilaterally, as well as through Japan–ROK and ROK–U.S. coordination—must now be elevated to an altogether new level.

2)    Nuclear Sharing

Against this backdrop, the second issue I wish to raise is the question of so-called nuclear sharing. I understand that in the Republic of Korea—where U.S. nuclear weapons were once deployed during the Cold War—this is being debated as a practical policy issue. According to surveys conducted by The Asan Institute for Policy Studies, some seventy percent of the Korean public supports the Republic of Korea’s possession of nuclear weapons.

Nuclear sharing is generally understood, as in NATO, to mean the peacetime deployment of U.S. nuclear weapons at bases in allied countries and, in a contingency, their wartime employment by allied delivery systems. Allies do not possess ownership of or command authority over those weapons; the final decision on whether they are used rests solely with the President of the United States. Yet I believe that even without physically hosting nuclear weapons on allied soil, it is still meaningful to regard as nuclear sharing an arrangement in which allies share in the decision-making process that could culminate in the use of nuclear weapons and share the attendant risks. Such an arrangement would, I believe, enhance the credibility of nuclear deterrence.

In Japan, the Three Non-Nuclear Principles—not possessing, not producing, and not permitting the introduction of nuclear weapons—remain firmly in place. In the only country ever to have suffered atomic bombings, there is, naturally, a deep aversion to nuclear weapons. Yet we must reconcile two imperatives: to seek sincerely a world without nuclear weapons and, at the same time, to think with the utmost seriousness about nuclear deterrence in order to preserve, at all costs, a world without nuclear war. Japan regards the preservation of the NPT regime as a matter of the highest importance, and we shall continue to devote every effort to that end.

Would not North Korea’s acquisition of the capability to strike the American homeland with overwhelming destructive force fundamentally alter the very nature of U.S. extended deterrence? I believe it is precisely for this reason that the debate over nuclear armament is being pursued with such seriousness in the Republic of Korea.

I do not believe that current efforts are sufficient to strengthen the credibility of nuclear deterrence in either the Japan–U.S. or the ROK–U.S. alliance. If we are to reinforce that credibility, we should urgently establish a standing framework—not only bilaterally, but trilaterally among Japan, the United States, and the Republic of Korea as well—in which our three countries can engage in continuous consultation and maintain close communication. I would be most eager to hear your views on this matter.

In this same context, I have also followed with keen interest the debate in the Republic of Korea over the possible introduction of nuclear-powered submarines: what strategic purpose they are meant to serve, what operational concept is envisaged, how their costs are being assessed, and how China’s likely reaction is being factored into the calculation. These, too, are matters on which I would greatly value your views.

3)    Responding to a Taiwan Strait Contingency

Let us suppose, for the sake of argument, that China were to launch a military attack on Taiwan. On sober reflection, is it not rather unlikely that it would simultaneously attack Japanese territory as well? Russia has waged a relentless and devastating war against Ukraine, yet it has not attacked a single NATO member. The reason is plain: the moment it turns NATO into a direct enemy, its chances of success diminish sharply. The same logic applies to the relationship between China and Taiwan. Even if China were to attack Taiwan, an attack on Japan would immediately make an enemy of the Japan–U.S. alliance. In Japan, one often hears it said that “a Taiwan contingency is a Japan contingency.” Yet if China were to refrain from attacking Japan, and Japan nevertheless were to determine that a situation threatening its survival had arisen and order defense operations accordingly, would that not risk Japan’s being seen by the international community as the party that initiated hostilities against China?

On the other hand, if China were to use force against Taiwan and the United States were to respond militarily, U.S. bases in Japan—among the most important strategic hubs in Asia—would almost certainly be operating at full capacity. That is precisely the kind of scenario in which prior consultation under the Japan–U.S. Security Treaty and the use of bases in Japan for combat operations would come squarely to the fore. Indeed, this issue has already arisen in concrete form in connection with the current situation involving Iran: the Spanish government, for example, chose not to permit the use of its bases by U.S. forces.

What, then, should Japan decide? If the United States were to raise the matter through prior consultation, I believe Japan would have virtually no realistic option but to agree. Yet if China were to resort to coercion or intimidation, it is difficult at present to predict how public opinion in Japan would respond. And in such a scenario, would the Republic of Korea not likewise face an equally momentous decision? North Korea’s actions, too, would have to be taken into account. It is entirely conceivable that North Korea, seeking to disperse U.S. forces, might undertake some form of action of its own—and such a development would serve China’s interests as well. The scenario we must fear most is the simultaneous eruption of a Taiwan Strait contingency and a contingency on the Korean Peninsula. To prevent such an outcome at all costs, we must deepen our strategic coordination. In the event of a contingency on the Peninsula, how would the United Nations Command, comprising nineteen participating nations, function in practice? And in connection with the use of the United Nations Command’s rear-area bases in Japan, how would the Agreement Regarding the Status of United Nations Forces in Japan be applied? These, too, are matters on which a shared understanding must be forged within Japan.

4)    An Asian NATO

In the Asia-Pacific, there is no collective defense framework akin to NATO. Yet I believe that, beyond the modernization of the Japan–U.S. and ROK–U.S. alliances and the strengthening of trilateral coordination, it is a matter of the highest importance to consider building such a framework for the broader Asia-Pacific. Several possible models may be envisaged.

First is the NATO model of collective defense: a framework under which an attack on one member is regarded as an attack on all, and joint action in common defense is undertaken as a matter of obligation. I am well aware that countries burdened by unresolved territorial disputes have faced obstacles to membership. Yet had Ukraine been a member of NATO, it would not have been subjected to Russian aggression. I do not entirely dismiss the view that NATO’s enlargement heightened Russia’s sense of alarm. At the same time, however, I wish to stress that the many states of Eastern Europe and the Nordic region that joined NATO after the Cold War did so of their own free will—not from any intention to invade Russia. Nor should we forget how tragically powerless the Budapest Memorandum, offered to Ukraine by the United States, the United Kingdom, and Russia, ultimately proved to be.

Second, unlike the NATO model, one can theoretically imagine a collective security arrangement—a kind of regional mini-United Nations—in which even states that might otherwise be regarded as potential adversaries would also be members. In such a system, however, any right akin to a veto would necessarily have to be kept under the strictest restraint.

Third, there is an OSCE-type framework, designed to promote dialogue across the region and prevent conflict. Asia already has the ASEAN Regional Forum (ARF), and there is certainly room to strengthen it further. Yet it would be difficult to say that this alone is sufficient.

Fourth, we could pursue a latticework of security cooperation, strengthening horizontal ties among countries that maintain security treaties with the United States and, over time, developing those ties into a NATO-like framework. I regard this as the most realistic path. Indeed, for more than twenty years, I have advocated closer coordination between the Japan–U.S. security arrangements and the Australia, New Zealand, and United States (ANZUS) system. A scenario in which the Republic of Korea and the Philippines are also incorporated into such a structure is, I believe, well worth serious consideration.

Each of these four frameworks has its own strengths and weaknesses, and naturally, they differ in terms of feasibility. Also, this is, to be sure, a matter internal to Japan. Although the Abe administration recognized the exercise of the right of collective self-defense in an extremely limited form, Japan still does not permit the full exercise of collective self-defense, nor the use of force in the context of collective security. That position rests on the constitutional interpretation long maintained by successive governments: namely, that such measures would exceed the minimum necessary scope permitted under the Constitution and, in effect, amount to the possession of war potential prohibited by the Constitution. Unless Japan overcomes this constraint—whether through explicit constitutional revision or through such means as the enactment of a Basic Security Law defining the limitations governing the exercise of collective self-defense—it will be difficult for Japan to participate in any new framework of this kind.

This symposium includes a session devoted to the idea of an Asian NATO, and I sincerely hope the discussion will be rich and fruitful.

5)    Strengthening Security Cooperation Between Japan and South Korea

On September 3 last year, the sight in Tiananmen Square of the leaders of China, Russia, and North Korea standing shoulder to shoulder came as a profound shock to us all. As the security environment in the Western Pacific grows ever more severe, the United States continues to find itself compelled to devote substantial attention and resources to the Middle East.

The fighting involving Iran must be brought to an end without delay. A closure of the Strait of Hormuz would not constitute aggression against any one particular state; rather, by obstructing the transport of Middle Eastern oil, it would threaten peace throughout the world. For that reason, the response should not be framed merely in terms of self-defense. It should be treated as a collective security measure based on United Nations resolutions, to be undertaken by a coalition of willing nations—including Japan and the Republic of Korea. Is it not incumbent upon our two countries to lead that discussion together at the United Nations?

From this perspective as well, close cooperation between Japan and the Republic of Korea is of the utmost importance for peace in the region and in the world. As a next step, I believe the conclusion of a Japan–ROK Acquisition and Cross-Servicing Agreement, or ACSA, is an urgent priority.

Throughout the long centuries of national seclusion under the Tokugawa shogunate, Japan maintained formal diplomatic relations solely with Korea as an exception. The influence of the great Neo-Confucian scholar Toegye Yi Hwang upon Japan is beyond measure. Like President Lee Jae Myung, Toegye hailed from Andong. He was a humble man of profound moral character who taught the moral path to which human beings ought to aspire. It is my earnest hope that cooperation between Japan and the Republic of Korea will always be guided by a vision of the international order grounded in moral principle and universal values.

Last year marked the auspicious sixtieth anniversary of the normalization of diplomatic relations between Japan and the Republic of Korea. Seizing that milestone as an opportunity, I earnestly hope that our two countries will deepen their candid dialogue still further and, working hand in hand, play an ever-greater role not only in securing peace in the Asia-Pacific but also in advancing peace throughout the world.