An agreement to ban the pre-determined use of nuclear weapons

Establish a treaty banning the pre-determined use of nuclear weapons

The war in Ukraine has brought the use of nuclear weapons to a state of possibility. An all-out nuclear war is no longer just a theoretical possibility, and such an event would involve the entire human race. To follow Clemenceau’s sarcastic quote about the very important war left in the hands of the generals, the rise of nuclear use and the nuclear deterrence strategy are very directly related to our lives for us to ignore it and leave it to military and security experts. In this column, I examine the state of the nuclear deterrence strategy as a story so that everyone can participate.

The rationale for mutual certain destruction – that is, “If a nuclear power is attacked with a nuclear weapon, it will counter-attack and destroy the other party and no one will survive.” Therefore, no one will start a nuclear war “- dangerous. There is a weakness and a distortion in this argument. For an analysis of the conflict between the framework of game theory and nuclear resistance, see Schelling (1960), Zagare (1992), and Kraig (1999).

First, the weakness: the argument for mutual certain destruction is correct in terms of game theory, but the assumptions behind the conclusion are very strong. The assumption is that, under perfect information, players have a thorough knowledge of their opponent’s behavioral motives and will act perfectly rationally according to their own behavioral motives. In reality, however, such an estimate is unpredictable. The world knows that information, motives and everything else about Russian President Vladimir Putin’s words and deeds are opaque.

The distortion in the argument of mutually certain destruction is that the goal of the conflict is out of proportion to the way it is achieved. In the argument of mutual certain destruction, the goal of each country is to ‘survive in the world’ and each country considers the ‘world’ as a means (i.e. hostage) to that goal. But the balance between the goal (survival of individual nations in the world) and the means used to achieve it (destruction of the world) is not proportional.

It’s like saying that a gang controlling Tokyo and a gang controlling Osaka are fighting to expand their power, and if the Osaka gang continues to lose, they will kill Tokyo’s 20 million inhabitants. Such threats, if managed, would make any goal (in this case, the expansion of gang power) meaningless.

First, there is no legitimacy in a game where the parties to the conflict have (largely undisputed) authority to determine the existence of the entire world. It is just as unreasonable to assume that gangs have the right to kill or maim the entire population of cities.

Such weaknesses and distortions need to be addressed and stable nuclear resistance considered. To overcome the weaknesses, nuclear forces must be prevented from climbing the ladder of nuclear growth because climbing that ladder will increase excitement and the likelihood of unforeseen events.

In order to overcome the distortion, we also need to define a game that involves the whole world (the rest of the world) as players outside the side of the conflict, who are unrelated to the conflict but will suffer huge losses in the use of nuclear weapons. .

The victims of nuclear war in the rest of the world are not just those who are currently living in non-partisan countries. All future generations are victims of the fact that countless generations could cease to exist – not just humans, but every living thing on earth. Whatever the cause, purpose or cause of the conflict between the two sides, it cannot justify endangering the future of all life on our planet.

In 2,000 years, the current invasion of Ukraine would seem like a meaningless conflict, not a risk to humanity’s survival – just as the causes of the Punic War 2,000 years ago are not important to us today. For the whole world, therefore, the main goal is to prevent conflicting parties from climbing the ladder of nuclear growth.

As a process to prevent a party from climbing the first step of the nuclear ladder, we may consider creating a treaty that prohibits the pre-determined use of nuclear weapons. Such an agreement would “impose immediate, unconditional and maximum sanctions against any country that initiates a nuclear pre-emptive strike.” All non-military sanctions can be used, including economic sanctions and other practical measures such as exclusion from the international framework.

It is the equivalent of establishing a new ideology that ‘a nuclear pre-emptive strike, even a limited one, is a criminal act against humanity that threatens the survival of all people unrelated to the conflict in question.’

Note that the rejection of the preemptive use of nuclear weapons is not consistent with the thinking of the current Japanese government. Although the Japanese government is unlikely to make such a proposal in the current situation, it makes sense to start with a blank slate to discuss new rules for nuclear resistance, including theoretical possibilities in response to the risks of nuclear use.

Let’s consider the effectiveness of the new agreement in a figure. Figure 1 shows the normal bilateral game of nuclear resistance. In a conflict between nuclear power A and B, A decides whether to launch a strike with limited use of nuclear weapons (LS) or not strike (NS), then B decides whether to counter-attack (C) or not (NC), And then A decides whether to counter-attack (C) or (NC). If both countries choose C, there will be an all-out nuclear war.

Figure 1 Bilateral game on preventing the use of nuclear weapons

Note:: This is an extension of a three-stage sequential game, where State A moves first, State B moves second, and then State A moves again.

If both countries are reasonable, in the case of equilibrium, state A imposes limited nuclear use (LS), but state B does not counter-attack (NC), and nuclear growth does not occur. Theoretically, all-out nuclear war is avoided. In the real world, however, once nuclear weapons are used, even to a limited extent, uncertainty spreads and the possibility of an all-out nuclear war is no longer zero.

Figure 2 shows what would happen if all the countries of the world joined an agreement that imposed a ban on the pre-determined use of nuclear weapons. In this case, the benefits of a pre-emptive nuclear attack by State A would be negative because of the limited use of nuclear weapons by the rest of the world. In Figure 1, it is impossible for State A to stop the limited use of nuclear weapons without sanctions. However, as shown in Figure 2, if it is known in advance that countries around the world will impose a ban on the use of nuclear weapons. State, State A will not use nuclear weapons in the first place because there is no benefit from limited nuclear use in the first place. Thus, the first stage of nuclear growth is prevented. Since nuclear use will not occur in equilibrium, sanctions will not be required and, as a result, sanctions-bearing countries will not have to bear any costs.

Figure 2 If many countries participate in a ban on the predetermined use of nuclear weapons

Note:: (X, Y) is the gain of (State A, State B)

Although the Nuclear Non-Proliferation Treaty came into force in 2021, the abolition of nuclear weapons is currently unrealistic because it cannot be achieved without the consent of all nuclear-weapon states. The treaty does not prohibit the use of nuclear weapons. If an agreement can be made to ban the pre-determined use of nuclear weapons, the sanctions can be enforced even if the signatories are non-nuclear-armed states. Thus, this agreement will create a new international standard with high credibility. Establishing such an agreement is tantamount to creating an international justice system where all the citizens of the world share the power to determine the fate of this planet equally.

Author’s Note: This column has been reproduced with permission from the Research Institute of Economy, Trade and Industry (RIETI). The original article was published in the Nikkei Shimbun on 15 June 2022 and was translated by RIETI with some additional information.


Craig, MR (1999), “Nuclear resistance in the developing world: a game-theoretical treatment”, Journal of Peace Research 36 (2): 141-67.

Shelling, TC (1960), Collision strategy, Cambridge MA: Harvard University Press.

Jagare, FC (1992), “NATO, Rational Growth and Flexible Response”, Journal of Peace Research 29 (4): 435-54.

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