The Treaty on the Prohibition of Nuclear Weapons (TPNW) came into effect on January 22 this year. 'Coming into effect' means that the treaty has legal force. Countries that ratified this treaty are known as states parties, and such countries are legally bound by the treaty. Nuclear weapons have finally been outlawed.
　In the past as well, there were various treaties formed to regulate nuclear weapons, such as the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the Comprehensive Nuclear-Test-Ban Treaty (CTBT). However, the TPNW is fundamentally different from these treaties. This is because, rather than reducing or controlling nuclear weapons, this treaty stipulates the complete prohibition and abolition of nuclear weapons. It is completely prohibited for any country to manufacture, possess, use, threaten to use nuclear weapons, or to assist such acts, under any circumstances.
　This is based on the rejection of nuclear weapons as inhumane. This is a bold shift from the previous approach, which aimed to strike a balance in the military force of countries. Over the past ten or so years, countries such as Austria and Mexico have pursued the international movement known as the Humanitarian Initiative, supported by the International Committee of the Red Cross (ICRC), International Campaign to Abolish Nuclear Weapons (ICAN), Mayors for Peace and more. More than anything, this movement was propelled forward by the hibakusha, the survivors of Hiroshima and Nagasaki, and those affected by nuclear testing around the world.

Civic actions to commemorate the TPNW coming into effect (January 22, 2021, Hiroshima and Nagasaki) (Hiroshima/photography: Mr. Takeo Nakaoku,　Nagasaki/provided by: Nagasaki Prefectural Citizen's Organization Promoting International Signature Campaign in Support of the Appeal of the Hibakusha for the Elimination of Nuclear Weapons)

■ The path towards banning nuclear weapons

　Pushed by the civic movement known as the World Court Project in the mid-1990s, the International Court of Justice (ICJ) deliberated on the legality of the threat and use of nuclear weapons. The mayors of Hiroshima and Nagasaki at the time attended the court hearings at ICJ in the Hague, the Netherlands, and testified to the horror of the damage from nuclear weapons and the illegality of their use. As a result, in 1996, the ICJ issued an advisory opinion that the threat or use of nuclear weapons would generally be contrary to international humanitarian law, and that there exists an obligation to pursue and conclude negotiations and leading to nuclear disarmament. This became the origin of the concept for a nuclear weapons convention.
　In 1997, a Model Nuclear Weapons Convention, based on the precedents of the Biological Weapons Convention (1972) and the Chemical Weapons Convention (1993) was proposed and discussions made progress. However, these did not immediately lead to negotiations for a treaty.
　In 2010, ICRC issued a presidential statement calling to prohibit and eliminate nuclear weapons as inhumane weapons, and this led to the kickoff of the Humanitarian Initiative movement. Three International Conferences on the Humanitarian Impact of Nuclear Weapons were held from 2013-2014, in Norway, Mexico and Austria. Statements were made by hibakusha, medical experts who have treated hibakusha, people who have been affected by nuclear testing and others. A common awareness was formed that the use of nuclear weapons can never be compatible with international humanitarian law, and that today if nuclear weapons are used, humanitarian aid would not even be possible.
　Based on that understanding, in 2015, discussions entered into the phase of legally prohibiting nuclear weapons. Learning from the Landmine Ban Treaty (1997) and the Convention on Cluster Munitions (2008), creating a treaty that first prohibits nuclear weapons and requires their elimination, details of which can be stipulated in a later stage, was thought to be a realistic approach. Providing assistance to the victims of nuclear weapons was also seen as a mandatory item.
　In 2017, the conference negotiating a treaty on the prohibition of nuclear weapons was held, presided by the Costa Rica. Hibakusha from Hiroshima and Nagasaki gave testimonies, and the word hibakusha was heard a number of times in the conference room. Since 2008, I have been traveling around the world on the Peace Boat's 'Global Voyage for a Nuclear-Free World'. We have been received by Mayors for Peace member cities, and have had mayors, diplomats and even government ministers listen to the hibakusha testimonies. In this way, the global community has become aware of the hibakusha as the witness of the inhumanity of nuclear weapons.
　On July 7, 2017, the TPNW was adopted with the support of 122 countries. The fact that the preamble of the treaty mentions the word hibakusha was reported in the news, but this was not something to be surprised of. The word was naturally incorporated in the treaty as the result of the efforts of the people of Hiroshima and Nagasaki as described above.

■ The power of the TPNW also changes nuclear weapon states

　This treaty stigmatizes nuclear weapons and greatly changes the way the world views nuclear weapons. It is true that because nuclear weapon states have not joined the treaty, they are not legally bound by it. Even so, there is now heightened political, economic and social pressure on nuclear weapons.
　Nuclear weapons have been outlawed, which means that they have become weapons that are not allowed to be used. Any country or leader that uses them would lose their political standing in the global community.
　At the same time, banks all over the world are divesting from corporations that manufacture nuclear weapons. When antipersonnel mines and cluster munitions were banned, the financial industry divested from companies manufacturing such weapons. As a result, such companies withdrew from their manufacture. The same thing is happening with nuclear weapons, and Japanese banks and life insurance companies are also joining this trend. This is linked to moves to pay consideration to the environment and Sustainable Development Goals (SDGs) when making investments.
　For antipersonnel mines and cluster munitions as well, the main countries who possessed such weapons have not joined the treaties. Nonetheless, the production of these weapons has fallen drastically, transactions have almost stopped, and their use is rejected. These treaties also changed the behavior of the countries that did not sign them.
　Nuclear weapon states now criticize the TPNW, saying that it is ineffective, and they put pressure on other countries to not sign or ratify the treaty. If they really thought it was ineffective, they would just ignore the treaty. The nuclear weapon states understand that the larger the number of countries that join the treaty, the riskier their own position becomes. In that light, the treaty is already effective. As the United States has the new administration with President Biden, attention needs to be paid to whether or not there is a change in the United States' adversarial stance toward the TPNW.
　If nuclear weapon states oppose the treaty, they will be required to explain how they have fulfilled or are planning to fulfill their nuclear disarmament obligation. In August this year, the NPT Review Conference that was postponed from last year is scheduled to be held. At that conference, the five nuclear weapon states will face even more serious accountability for disarmament than they have before.
　The TPNW and the NPT do not contradict one another: the enactment of the TPNW will be a major force for advancing nuclear disarmament as provide by the NPT.

■ To the first Meeting of States Parties

　The next focal point is the first Meeting of States Parties (MSP), which is to be held in January 2022 in Vienna, Austria. After that the MSP will be held once every two years.
　At the first MSP, there should be a discussion on measures to increase the number of states parties towards universalization of the treaty. A total of 122 countries have supported the adoption of the treaty, but the number of states parties is still only 54 (currently at April 30). Another issue to be tackled would be preparing to have countries with nuclear weapons join the treaty in the future. This means developing practical measures for irreversibly dismantling nuclear weapons within a set time frame, with effective international verification.
　It is also necessary to ensure that the states parties fully implement and adhere to the treaty. The treaty provides that states parties must not assist or encourage the use or possession of nuclear weapons by other countries. Thus, the definition of assisting or encouraging needs to be clarified. States parties are also obligated to provide assistance to victims of nuclear testing and remediate environments that have been polluted by radiation. States parties are required to develop concrete action plans for that purpose.
　States not party to the treaty and NGOs can join the MSP as observers. The Japanese government has indicated that it has no intention of signing or ratifying the treaty, but it should at least participate in the meeting as an observer. This is truly an area to which Japan could contribute. For example, in terms of assisting the victims of nuclear testing, Japan has experience of providing support to the hibakusha in Hiroshima and Nagasaki, as well as decontamination work in Fukushima. It is this kind of contribution that is greatly required. In addition to the Japanese government, experts and those from organizations involved in the medical treatment and supporting the rights of the hibakusha have very important roles to play. Countries with and without nuclear weapons should also work together to develop an international mechanism to effectively verify nuclear disarmament. The Japanese government positions itself as a 'bridge' between these countries, and as such there are high expectations for its contribution.

■ True security will only be achieved with the abolition of nuclear weapons

　The current objective of ICAN is to reach one hundred states parties within a few years. As we continue advocating in many countries, we would like to get a country that is currently under the so-called 'nuclear umbrella' to also sign and ratify the treaty.
　The governments of Japan and the member countries of the North Atlantic Treaty Organization (NATO) still believe that nuclear deterrence is essential for their security. It is not easy to shift this way of thinking. Nonetheless, through repeated discussions, change is possible.
　First, nuclear deterrence is a policy predicated on the use of nuclear weapons. Japan is the country that knows better than any others the horrific consequences that the use of nuclear weapons brings―is it morally acceptable, then, that Japan has such a policy?
　The next question is, does nuclear deterrence really work? Reckless parties who are prepared to a suicidal attack will not be deterred. There are risks of detonation of nuclear weapons by accidents and errors. There also are new risks emerging, such as cyber attacks and misuse of artificial intelligence.
　Additionally, if one country claims the right to have nuclear weapons for their security, their adversary will also do the same. This leads to a nuclear arms race. Today, the global community faces threats such as climate change and infectious diseases. Is there really any room for us to pour resources into nuclear weapons?
　If, for some reason, deterrence fails and nuclear weapons are actually used, who is going to take responsibility for the consequences? 'It was unexpected' will not be an acceptable answer.
　When we look back over history, in the past there was the slave system, and women did not have the right to vote. These are examples of abnormal situations that are unthinkable according to today's values, but were thought of as normal at the time. More and more people bravely spoke out against these abnormalities, which led to the creation of new laws, which changed society. Of course, just because a law was created does not necessarily mean that society was improved straight away. Laws were enacted, people made efforts to align society to the state stipulated in the laws, and as a result the bad old system disappeared.
　When new values emerge, people who have profited under the old values get angry and threaten people, saying that the new values are 'unrealistic'. There are people who say that abolishing nuclear weapons is 'unrealistic', but this is a temporary phenomenon. The end of nuclear weapons is already beginning. The true end will come as the result of our individual awareness and action.

(Submitted February 2021 and updated April 2021)

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