The North Korea–United States Summit and Possibilities for New Security-Oriented Thinking

ABSTRACT In this paper, the first in PSNA Working Paper Series, the author demonstrates that we are now entering an era when nuclear deterrence as a security measure is ineffective, by taking an example of the issue of North Korea’s denuclearization talks. Unlike in the Cold War era, the international society has become more interconnected, and each country’s economy is dependent on that of other countries. Destroying another nation through war is now the equivalent of destroying part of one’s own economic foundation. The current concern, therefore, is not the physical destruction of the world due to nuclear retaliation by the United States or China, but rather “mutually assured economic destruction” in which the global economy becomes dysfunctional. However, even if it is now apparent that a war option is not viable, Japan still sticks to US extended nuclear deterrence. The author examines why and how disadvantageous it is for Japan to continue to rely on nuclear deterrence to defend against the threat of North Korea. If it is possible to eliminate North Korea’s nuclear program through negotiation and giving incentives, it would demonstrate that an approach other than deterrence could be successful.


Introduction
Since the North Korea-United States summit took place in June 2018, both countries have been in discussions regarding North Korean denuclearization. To break through the current stalemate in these discussions, a second summit meeting is anticipated in late February. Whatever results these talks may produce, the fact that nuclear disarmament is a topic signifies a new age in the history of nuclear weapons.
We have been accepting the existence of nuclear arms as "a necessary reality" to prevent wars, while maintaining policies on how to avoid using them. Despite taking a long time to achieve the denuclearization of North Korea, if we find that it is possible to eliminate a nuclear program through negotiation, it would demonstrate that an approach other than deterrence could be successful. As a real-life case study, the North Korea-United States talks offer an opportunity to consider new possibilities and create experimental models for these.
Speaking as a former defense establishment insider during the age of mutual nuclear deterrence, I find this degree of change rather shocking, and this has prompted me to try to contribute to a better understanding of this new era by identifying some of the tools to do so. No one can be certain where the North Korea-United States negotiations are heading, but what is certain is that change is coming. We are at the end of an era and the beginning of a new one.
Why is the Japanese Prime Minister Unable to Respond to the Current Situation of the Atomic Bomb Victims?
On 9 August 2018, 73 years after an atomic bomb was dropped on Nagasaki, Prime Minister Shinzo Abe visited Nagasaki City and met with the victims. A representative of the victims asked why the Prime Minister did not mention the Treaty on the Prohibition of Nuclear Weapons in his speech. In response, the Prime Minister didn't answer the question but reiterated the Government's position that countries have diverging views on nuclear weapons, and it is important [for Japan] to act as a bridge between these.
The Japanese government's position is that as long as nuclear weapons exist and pose a threat to national security, Japan needs the nuclear umbrella of the United States. If Japan supports a treaty that considers nuclear weapons unlawful, Japan's security policy could no longer be based on the nuclear deterrence capacity of the United States.
The government believes that the US nuclear weapons that once nearly destroyed our nation are "a necessary evil". Indeed, there exists no weapon greater than a nuclear bomb. Therefore, there is a good reason to believe that the existence of a nuclear program is necessary to prevent the threat posed to us all. However, this line of thinking does not stop at a passive acceptance of nuclear programs as an unavoidable reality, but actively justifies their existence as part of our national security policy.
During the Obama presidency, the Japanese government opposed the No First Use declaration by his administration. They believe that the ability to retaliate against nuclear weapons is not sufficient in and of itself; rather, there must be room to use nuclear weapons when attacked otherwise war cannot be prevented. However, if the use of nuclear weapons is not limited to retaliation against a nuclear attack, no threshold restricting the use of nuclear weapons remains.
That is, indeed, the logic of nuclear deterrence theory. In response to an attack, one retaliates with the ultimate weapon, one that has the potential to cause annihilation. If there is always a risk that attacking Japan could provoke such a response, who would attack Japan? This is a convenient logic if we are only concerned about our own wellbeing. However, the problem with this logic is when it is applied to other countries as well. For the United States, using nuclear weapons to prevent an attack on its ally, Japan, is a difficult decision because the United States itself could in turn suffer major damage. This is because the only countries with the ability to attack Japan on a scale that would require a nuclear response would be major military powers such as China and Russia, not North Korea.
If Japan is under the US nuclear umbrella, it follows that when Japan is attacked, the United States will use nuclear weapons in response. There is great irony in the only nation that suffered atomic bombings, Japan, maintaining national security assumptions of the use of nuclear weapons by its major ally. The oath "this mistake shall not be repeated" on the Memorial Monument in Hiroshima, the City of Peace, forces us to wonder if "mistake" does not include the use of nuclear weapons against enemies of Japan.
The North Korea-United States summit held last June had no impact on the attitude of the Japanese government. The Outline of the National Defense Program that was adopted by the government last December states, "the extended deterrence of the United States, including nuclear deterrent force, is essential against potential nuclear threats". Regarding North Korea, "Although it declared its intention to denuclearize, its nuclear and missile programs have not changed", and as such, North Korea "remains a serious and imminent threat to Japan" (Japan Ministry of Defense 2018).
In any case, a path toward the total abolition of nuclear weapons will never be found under assumptions that nuclear weapons are necessary. It is easy to criticize the government's attitude, but what the government really needs is clear logic that will prevent war, and if no other assurances than nuclear weapons are found, the government can hardly be expected to change its thinking.
If we are to "act as a bridge between countries with diverging views" as the Prime Minister suggested, we must repeatedly examine the meaning of changes in North Korea, the extent to which the idea that nuclear weapons will prevent war holds water, and the potential of any other prospective approaches. Here if anywhere is a rift in viewpoints that requires bridging.

From Pressure to Conversation
In 2017, North Korea pursued a policy announced by Kim Jong-un at the beginning of that year that allowed for repeated nuclear tests and firing of missiles. In response, the United States stepped up economic sanctions and applied military pressure on the country by deploying multiple aircraft carriers and bombers in South Korea and around Japan. However, North Korea did not implement any changes in its nuclear program, leading to a stalemate. As more pressure was exerted, the risk of accidental war increased, and the concerns of nearby countries, including Japan, were heightened.
In 2018, North Korea declared that its nuclear arms development was complete and changed the focus of its policies to economic development. North Korea explored the idea of discussions with South Korea in conjunction with the 2018 Winter Olympic Games in Pyeongchang. Moreover, during the April 2018 Inter-Korean summit, the two countries jointly declared denuclearization of the Korean peninsula and an end to the state of war. Kim Jong-un requested a meeting with the United States through South Korea, and President Trump met with him at the North Korea-United States Summit on June 12 in Singapore. They agreed on security guarantees by the United States in exchange for the denuclearization of North Korea.
Subsequently, North Korea and the United States have been bargaining intermittently in an effort to implement the agreement reached in principle at the summit, but it remains unclear how the United States, which wants to verify the status of North Korea's nuclear weapons and facilities, and North Korea, which seeks to alleviate economic sanctions, can find a middle ground. Clear steps toward officially ending the Korean War are yet to be made, which would represent an important form of progress toward security guarantees.
The United States and Japan suspect that North Korea has no intention to abolish its nuclear program but is simply attempting to get sanctions lifted by compromising with the Trump administration. However, the logic behind international negotiations is not that simple. The parties came to an agreement because benefits were to be gained from doing so, and to protect such benefits, they are obliged to comply with the agreement.
If getting the sanctions lifted is North Korea's primary aim, and their driving concern is therefore economic in nature, this implies that more diverse and flexible negotiations could be more successful than relying strictly on military means.
The outlook for negotiations is not necessarily grim as long as there is a will to compromise.

Leading with Force and Benefits to Achieve Goals
War is the use of violence by a nation to exert its will. The root of the problem with North Korea is the conflict between North Korea's desire to retain its nuclear program and the United States' unwillingness to accept it. To change North Korea's position, the United States has made threats in the form of sanctions and military power.
The intent behind sanctions was to cause enough economic loss that the North Korean economy would collapse and the regime would lose its power. These changes would be brought to North Korea by inciting fear that the regime itself would be overthrown through war. However, North Korea never changed its stance.
The benefit for North Korea of retaining its nuclear program is enhanced security against an US attack. Therefore, as the conflict intensified, the benefits related to having nuclear weapons also increased. On the other hand, the main benefits for the United States are to remove the threat to its own safety posed by North Korea's offensive capability and to increase its legitimacy as the nation that maintains order by achieving the abolition of other countries' nuclear weapon programs and preventing further complication of power relationships in the region. For these reasons, increased North Korean nuclear capacity is disadvantageous to the United States.
The United States defined Iran, Iraq, and North Korea in 2002 as "the axis of evil" and declared a policy aimed at altering the situation, potentially through a preemptive attack. The axis of evil referred to "countries with weapons of mass destruction, or that wish to acquire weapons of mass destruction in defiance of the United States". The United States accomplished regime change in Iraq but failed to build a stable postwar order there. In North Korea, the United States has attempted denuclearization by force and made threats that hinted at direct regime change, such as through the murder of Kim Jong-un. However, when ultimately the DPRK refused to change its position, the United States did not feel that openly declaring war was viable.
The US military probably has enough power to destroy the Kim Jong-un regime. However, a war to overthrow a regime because it is developing a nuclear program, when that country has not declared war against another nation, cannot be justified under international law. Should a war ensue, South Korea (which is within range of North Korean long-range artillery) and Japan (within range of intermediate-range missiles from North Korea) would almost certainly sustain damage. Furthermore, North Korea would fall into a state of anarchy if its current regime were overthrown. To establish a new order out of such confusion, North Korea would have to be occupied for a long period by about a million soldiers. In view of the high costs and limited benefits, war was simply not an option for the United States. In the event that the North Korea-United States negotiations collapsed while these conditions remained unchanged, war would still not be a viable option.
If war is not an option, the threat of military force is ineffective as a means of forcing North Korea to bend. If anything, it unites North Koreans and strengthens their will to keep their nuclear program. This situation led to the 2017 stalemate.
The ultimate goal for the United States is to change North Korea's desire to keep its nuclear program. There are two ways to change someone's will: forcibly or by offering incentives. If the threat of war is ineffective in changing North Korea's position, the only option left is to entice the regime with benefits. What North Korea wants more than anything is a guarantee that the United States will permit its regime to exist, in exchange for which it would not attempt to destroy the United States. Similarly, what the United States wants is for North Korea to abandon its nuclear program, in exchange for which the United States would not seek to overthrow the North Korean regime.
The agreement reached at the North Korea-United States Summit constitutes a promise to offer these concessions to each other. Having both countries grant what the other side desires without the use of force is the surest and most effective method of avoiding a war. If countries can obtain what they want without a war, they would never choose war, which has very high costs and no assurance of a favorable result.

Both Cannot Return to the Past
Of course, the best scenario would be for North Korea and the United States to achieve their mutual goals through negotiation. As long as they perceive an opportunity to negotiate, there is no reason for either country to take a course of action that would jeopardize such an opportunity. With the June 12 North Korea-United States agreement as a good point of departure, it is imperative that these nations move toward resolution of the issue.
For North Korea, nuclear abandonment equals military disarmament. This is because North Korea does not have the ability to threaten US safety with conventional military power alone. This situation has made North Korea cautious. North Korea cannot ignore the risks related to the potential identification by the United States of the locations of its nuclear weapons; that is, the US military would immediately intervene to destroy them. Thus, the next challenge for the United States is how it can gain its counterpart's trust in its assurances that it would not seek to overthrow the regime.
The origin of the North Korea-United States conflict dates back to the 1950 Korean War. Despite a cease-fire being declared under the 1953 Korean Armistice Agreement, the countries are still technically at war. It is a natural course of action for countries at war to pursue military superiority. To build trust between North Korea and the United States, the Korean War must be officially ended. Once the conflict that persists due to the ongoing state of war is eliminated, the fear of an attack by the United States should also be eliminated, and there would no longer be any reason to maintain nuclear weapons.
The achievement of these ends, however, requires the involvement of the major parties to the Korean War and the establishment of the postwar order on the Korean peninsula. This includes not only the United States but also China. Such a multilateral agreement is vital for ending the war, and it would mark the start of a postwar framework for new talks in northeast Asia including South Korea, North Korea, the United States, China, Japan, and Russia. Here again, formally ending the Korean War is a prerequisite for achieving denuclearization. Only after a multinational framework is established to handle regional security issues in northeast Asia can the denuclearization of North Korea be finalized.
Meanwhile the North Korean regime is negotiating for guarantees. It is deeply committed to improving its economy through increased access to investment opportunities brought by the lifting of sanctions. Since North Korea has no bargaining chips other than its nuclear weapons in its negotiations with the United States, the road to the country abandoning its nuclear weapons is a long one. Its two motivations, achieving a guarantee of stability of its regime and economic improvement, are closely interrelated.
This does not mean that the situation will necessarily progress at the pace set by North Korea. The more pressing its economic needs become, the more flexible with its incentives the United States can be. For this reason, North Korea is attempting to push the United States toward compromise by involving China.
By the time this paper is published, the second North Korea-United States Summit, scheduled for late February, will already have taken place. Though steps for North Korea to take toward denuclearization and for the United States to lift its nuclear weaponsrelated sanctions are to be discussed, things might not turn out as expected. At this point, even forecasting the results of the negotiations is not feasible; the most we can do is to discuss the logical path toward resolution of the issues, nothing more, and nothing less.
In any case, what is important to recognize is that it is possible to solve the North Korean nuclear weapons issue through incentives rather than force. There is a path to solving problems without war. The question is how we can generalize, customize, and systematize this potential.

From Deterrence to Incentives: The Possibility of a New Mind-Set
The core incentive for Kim Jong-un is to ensure the stability of his regime. He has no prospect of winning a military resistance against the United States. Being sanctioned for opposing the United States will weaken his regime, and if the conflict leads to war, his regime will collapse. Beyond the military situation, the second key to a stable North Korea is a sounder economy.
To rebuild the North Korean economy, economic sanctions must be lifted. North Korea appears to be attempting to outsmart the sanctions, but in a nation of 20 million people, smuggling and backroom deals cannot provide economic growth. To grow the economy, economic participation in the international market is essential; this means that North Korea must abandon its nuclear program, which is the cause of the sanctions. Kim Jong-un must be aware of this. At the same time, for it to start to feel confident about the discontinuance of its nuclear program, North Korea must first remove the risk of military conflict with the United States.
If Kim Jong-un axes his strategy based on incentives such as these, the increased availability of incentives presents an opportunity. Of course, this is only a hypothesis that will be put to the test in the actual negotiation process.
What makes this process important is that both North Korea and the United States have transitioned from conflict and deterrence, backed by their ability to attack each other, to negotiations based on offering each other incentives. In other words, instead of seeking to force each other to bend through threats or actual war, they are opting for persuading each other through incentives. Herein lies potential to drastically change both parties' perceptions and approaches to attaining assurances of security.
The main framework for security assurance has changed over time. In the nineteenth century, the primary approach was to solve international conflicts through war. In the twentieth century, the mainstream approach was to use force as a deterrent to prevent war. What we are experiencing today could be the first step toward a new approach of solving problems through mutual compromise based on incentives.
To effectively transition from deterrence to incentives, I would like to examine the future of the North Korea-United States agreement, which I believe contains the greatest potential significance for North Korea-United States reconciliation efforts.

Can We Prevent Missiles with Deterrence?
In his address to the National Diet on 14 February 2018, Prime Minister Abe stated, "When North Korea launches a missile, the only nation jointly protecting Japan is the United States. If they miss intercepting the missiles, the only country that can retaliate is the United States. Unless [North Korea] takes this to heart, it may take reckless action going forward". Abe's statement is a summary of the concept of deterrence, in which the intention to attack is countered by threat of even more powerful retaliation.
For this logic to be borne out in facts, three prerequisites must be met. The first is that the United States would indeed retaliate, ignoring considerations of its own benefits and risks; the second is that North Korea would hold back from launching missiles due to fear of retaliation by the United States. Since the "if they miss" scenario implies missiles potentially landing in Japan, a third unstated possibility is that Japan could withstand such a missile attack and request retaliation by the United States, including the use of nuclear weapons.
None of these assumptions is certain. If North Korea were to begin a war that involved the use of missiles, it would be under a definite state of confrontation with the United States and would be willing to target the United States (or perhaps its ally Japan) with nuclear weapons and ICBMs. The following questions arise: Would the United States be prepared to sacrifice itself to retaliate against North Korea to avenge Japan? War sometimes begins out of fear, and North Korea might consider that preemption is the only way for them to survive, just as Japan Imperialists did in 1941. Furthermore, would Japan be able to withstand missile attacks on Tokyo or its nuclear plants? The logic of deterrence with force may appear solid, but it presumes the power to prevail in an armed conflict and, in war, one must be ready to withstand damage.
In the end, PM Abe's "deterrence through the US retaliation" on Japan's behalf is a weak proposition. Personally, I would give each of the three assumptions a 50 percent rating for reliability. When the three probabilities are multiplied, we get 0.5 × 0.5 × 0.5 = 12.5%. Can a security assurance policy with a 12.5 percent likelihood of success survive? This is why an alternative to the idea of deterrence is necessary.
The most certain way to stay safe from missiles is not to "strike down a missile and retaliate", but to eliminate the willingness to use missiles. Making military threats ends up increasing the ability and willingness of the counterpart to strike. If a nation cannot strike back in response to a missile attack, the most realistic defense is to eliminate the willingness to use missiles.
The North Korea-United States negotiations seek to ensure North Korea would not launch its missiles under any circumstances before the actual abolishment of its nuclear weapons program takes place. What is necessary going forward are continued efforts in this direction and monitoring to ensure it is final and verifiably irreversible.

Why are Nuclear Weapons Unusable?
War is an act of confronting another country with violence to achieve one's political goals. Deterrence involves discouraging violence by demonstrating the ability and resolve to use even more violence to suppress other actors' willingness to go to war. To achieve realistic deterrence, one party requires a means of violence and must convince the other party that they are determined to actually use such violence.
In other words, nuclear weapons' function as a deterrent is based on the thought process by which the other nation recognizes the possibility of actual use of nuclear weapons, which prevents it from attacking. However, a nation that fears nuclear weapons must plan for the possibility of an attack. Nuclear weapons have the power to destroy not only opposing military forces but also whole cities. If troops who are seeking to force another country to bend to their will are destroyed, the enemy might retaliate by destroying cities, thereby seeking to destroy the core of its opponent's resolve, the nation itself.
If a war goes beyond its initial purpose of forcing another country to bend to its will in this way and ends up seeking the annihilation of the nation itself, the war becomes suicidal and loses its significance as a means to achieve a political goal. During the Cold War, the common understanding of mutually assured destruction (MAD), which signified recognition that the United States and USSR could both be destroyed by nuclear weapons if they engaged in a blind pursuit of victory, kept them from actual war.
The reason the Japanese government believed that extended deterrence under the US nuclear umbrella, considered the foundation of its security assurance policy, was effective is because if one of the two nuclear superpowers during the cold warthe United States or the Soviet Unionattacked the other, allies would retaliate, creating a potential risk of nuclear retaliation. This assumption resulted in the deterrence of military aggression even against allies.
In other words, nations were prevented from going to war because their prospective combatants owned nuclear weapons. Since they could not go to war, the United States and USSR had to coexist, leading to a strategic stability that was called détente. Nuclear weapons were acknowledged to have an ability to deter war simply by their existence, and their existence was justified because they had not yet been used.
However, this relationship is based on the assumption that both countries are still willing to use nuclear weapons if deemed necessary.
The East-West conflict during the Cold War did not involve mutual economic interdependence, and there was no room to budge due to the opposing ideologies characterizing the two sides. In this conflict structure, in which each side firmly rejected the other's ideology, the perceived superiority of one side would cause fear in the other. The three causes of war as defined by Thucydideswealth, honor, and fearcoexisted in this conflict. War could happen at any time, and once a war was launched, there would be nothing to stop it from spreading. If it did not stop spreading, it could escalate to the use of nuclear weapons. A country under attack may have retaliated with nuclear weapons, resulting in the risk of its own annihilation. In this manner, nuclear weapons became unusable because both countries' willingness to use them was recognized. This is the essential concept of nuclear deterrence through mutually assured destruction, as well as of extended deterrence under the nuclear umbrella.

Differences in Motivations for Nuclear Weapon Use between the Cold War and the Present
The conflict between liberalism and communism or totalitarianism during the Cold War was a conflict between modes of existence. Both sides had strong beliefs -"I would rather die than lose my freedom under totalitarianism" and "we cannot allow ourselves to be exploited by capitalism"that justified each side's regime. This was a conflict with no compromise, and it was considered worth pursuing even at the risk of being destroyed by nuclear weapons. In other words, political motivations that created the willingness to use nuclear weapons existed on both sides.
Today, no such absolute ideological conflict exists between any two nations. The world has become one market controlled by economic competition. Enormous amounts of capital move across national borders, and each country's economy is dependent on that of other countries. Destroying another nation through war is now the equivalent of destroying part of one's own economic foundation.
Dictatorial political systems and their domestic restrictions on human rights may sometimes become a political issue, but this is a problem within a single nation, not a challenge to global governance as the communist world revolution was. Presently, no threat exists that must be prevented to avert a nation's downfall. There is no "life-ordeath" conflict that could lead to irrational decisions.
Today, there is concern over a possible war between the United States and China over supremacy according to the "Thucydides trap". Competition over trade and advanced technology continues to intensify. However, the true nature of this conflict is over economic and technological supremacy, and the fear that the United States experiences as it contemplates the possible loss of its supremacy is the exacerbating factor. This problem cannot be solved by either forcing the other side to surrender by war or by destroying the other in war.
The current concern, therefore, is not the physical destruction of the world due to nuclear retaliation by the United States or China, but rather "mutually assured economic destruction" in which the global economy becomes dysfunctional.
The logic of mutually assured destruction appears to persist between major nuclear powers. However, the big differences between the Cold War and today's situation is the lack of motive to resolve conflicts through war and the unwillingness to destroy one's opponent with nuclear weapons at the risk of one's own destruction, even if one has to put up with some antagonism or harassment as a result.
Without a motive, there is no will to use nuclear weapons. If this is the case, does the argument that nuclear weapons without the willingness to use them effectively represent a situation of deterrence still hold water? Even if there is no longer any motive for war between major states with nuclear weapons, some wars between a major nuclear state on one side and a medium-size or small state without nuclear weapons on the otherfor example, the annexation of Crimea by Russia, the capturing of islands in the South China Sea by China, and the Iraq war waged by the United Stateswere not prevented.
Could these wars have been prevented if these small nations had nuclear weapons? Perhaps. This is exactly the motivation underlying North Korea's drive to keep its nuclear weapons program. However, even if these lesser nations had armed themselves with nuclear weapons, they would not have reached parity with major states that have larger nuclear arsenals, and they would have had no hope of winning a war. Acquiring nuclear weapons may even increase the risk of being attacked by major states with nuclear weapons. The actual problem was that these nations were not under the nuclear umbrella of major states with nuclear weapons, and thus the attackers had no concern about provoking a war with another major state that possessed nuclear weapons. In other words, there was no motive for major states to use their nuclear weapons, and thus the existence of nuclear weapons did not prevent war in these cases.
What about the allies? If medium-sized and small nations are under the nuclear umbrella of major states with nuclear weapons, could they avoid being attacked by other major states that have nuclear weapons? This logic seems to be moderately persuasive. However, today, as the logic of mutually assured destruction between major states with nuclear weapons is waveringin other words, now that it is unclear whether major nuclear states are willing to go to war with another state that possesses nuclear weapons even at the risk of their own demisethe root question of whether the nuclear umbrella is secure cannot be answered.
Crimea, the South China Sea, and the Iraq war were all major incidents that affected the international order, yet major states with nuclear weapons showed no will to go to war in these cases. If a nation is closely allied with a major power, an attack on that nation might have a greater chance of leading to war, but whether it should be protected with nuclear weapons is a different question.
At present, the main factor that deters war between major nuclear states is not the existence of nuclear weapons, but the lack of perception that going to war would resolve any problem, compounded by the realization that the use of nuclear weapons would lead to the loss of an opportunity to become involved in negotiating incentives between major states. In our contemporary situation, no clear strategies exist for offering or negotiating incentives as power continually shifts between major states. Therefore, problems cannot be solved through the short-term destruction of the balance of power that we call war; that is the nature of the times we are living in.
In any case, the logic that the existence of nuclear weapons prevents a war between states is useless in solving the problems of this day and age.
On the other hand, armed groups called terrorists are supported by ideologies that deny other people's very right to existence, and they are willing to pursue their ideologies even if it means their own deaths. Their objective is murder, not rule. That is why they are called terrorists. Since they do not have a state, land, or people to rule, they have no state or culture to worry about losing through nuclear attacks. Therefore, it is difficult to stop terrorism with military force.
Today, the great global risk is the possibility of nuclear weapons, which are no longer used as a tool of war between states, falling into the hands of terrorists, who might then use them as a means of murder, not deterrence. This is why the management of nuclear weapons by states, as well as of nuclear technology and of the transport and disposal of related materials, has come under criticism. Terrorist groups, which are not states, would never ratify the Treaty on the Prohibition of Nuclear Weapons. Hypothetically, even if a world without nuclear weapons were achieved in the future, the threat of terrorists developing and using nuclear weapons would remain an issue for international society. Conflict among human beings, not just among states, must be resolved if we wish to eliminate all forms of violence and destruction. To that end, nuclear weapons and military power are not the solution.
A new approach that moves away from deterrence by nuclear weapons is thus needed.

The US Nuclear Strategy in Confusion and the Security of Japan
The US Objective of Enhanced Nuclear Capacity The Trump administration did not rule out the preemptive use of nuclear weapons during its Nuclear Posture Review of February 2018, which stated that the United States aims to develop "usable nuclear weapons" with limited objectives, such as low-yield nuclear weapons and cruise missiles. This represents an attempt to devise nuclear options applicable to all war-related purposes, from the destruction of limited military targets to the annihilation of an enemy nation, and to gain absolute superiority to win all wars involving nuclear weapons by making all other countries powerless to mount effective attacks. Considering that the true nature of deterrence is the power to win a war, such steps would enhance the deterrence capacity of the United States.
Of course, there remains the dilemma of security assurance. Actors who do not want to see the United States gain unquestioned superiority may act to further strengthen their own nuclear military power, resulting in the start of a new cycle of the nuclear arms race.
During the Cold War, mutual deterrence based on nuclear weapons was grounded on the assumption of mutual vulnerability, that is, the belief that neither combatant could survive a nuclear attack. If either party is assured of its ability to avoid damage and achieve victory, mutual deterrence falls apart. This would no longer be deterrence but a unidirectional coercion based on the threat of violence, and if it were ever actually put into practice, it would constitute massacre without justification.
US opinion is that if the only nuclear weapon that the United States owned was large long-range missiles launched from its mainland, while the enemy possessed smaller nuclear heads along with intermediate-range missiles with the capability of forward deployment against the United States, the US nuclear weapon would be too large to retaliate against limited nuclear attacks by their enemy, thereby making it unusable. In this case, the United States would lack any way of retaliating against limited nuclear attacks.
From Japan's standpoint, if the United States has diverse military options including intermediate-range nuclear weapons, its deterrence capacity would increase. However, there is a serious problem with this line of thinking.
Negative Impact on Japan's Safety First, the US aim is to have usable nuclear weapons. Low-yield nuclear weapons with limited power would be deployed against conventional military weapons of the enemy. If nuclear weapons are used against conventional weapons, the generally accepted threshold for the use of nuclear weapons would disappear.
Second, low-yield nuclear weapons must be available at the front lines in a usable form. Equipping the front lines with powerful military force is effective as a deterrent in a crisis, but it could also strike fear in enemies' hearts since it implies an ongoing state of crisis, possibly leading to a preemptive attack.
Third, if low-yield nuclear weapons are used in the battlefield, retaliation with intermediate-range nuclear weapons from behind the front lines can be expected. Japan, where the US military's command and supply functions for northeast Asia are centered, would be an ideal target for intermediate-range nuclear weapons.
Fourth, intermediate-range nuclear weapons with a range of less than 5500 km could reach Beijing if launched by US military forces stationed in the western Pacific Ocean. On the other hand, intermediate-range nuclear weapons owned by China could reach Tokyo but not the United States. What this means is that the United States could enter a nuclear war with intermediate-range missiles without fearing an attack on its own soil. Therefore, there is a major difference between Japan and the United States in the degree of threat from intermediate-range nuclear weapons, and this is leading to a new age of "decoupling".
The 1987 INF treaty was concluded because NATO nations were concerned about such decoupling. In that instance, Soviet intermediate-range nuclear missiles could not reach the United States but did threaten Europe, rendering the USA retaliation strategy dysfunctional. Accordingly, the United States purposely equipped Europe with intermediate-range nuclear weapons, which was followed by the United States and USSR abolishing these weapons simultaneously.