7 July 2017 was a momentous day for disarmament and arms control. On that day, 122 states approved the Treaty on the Prohibition of Nuclear Weapons, often called ‘the ban treaty’, at the United Nations in New York. Once 50 states have ratified the treaty, nuclear weapons will be illegal. The agreement will prohibit the possession of nuclear weapons for all states in the same way as the chemical and biological weapon conventions have prohibited those weapons for all.
In the final report of the 2010 Non-Proliferation Treaty (NPT) Review Conference, the parties to the treaty expressed ‘their deep concern over the catastrophic consequences of any use of nuclear weapons’. Since then, it has taken three international conferences to debate these consequences, a humanitarian pledge signed by over 100 states and a UN Open-ended Working Group to agree to start negotiations on a prohibition treaty. Consequently, the treaty is above all a humanitarian achievement recognizing the indiscriminate nature and uniquely destructive power of nuclear weapons.
This is also reflected in the process. Civil society has been an organic part of the negotiations. The voices of the victims of nuclear weapons and nuclear weapon testing have been heard as never before. In her deeply moving closing statement, Setsuko Thurlow, an atomic bomb survivor, said: ‘This is the beginning of the end of nuclear weapons’.
The Nuclear Non-proliferation Regime
None of the world’s nine nuclear-armed states participated in the negotiations. Nor, at least in the near future, will they be among the states to ratify the treaty. They continue to claim that nuclear weapons are an indispensable part of their security while at the same time actively working to prevent other states from developing them.
Most of the nuclear-armed states and the states protected under the so-called nuclear umbrella voted against negotiations on the Treaty when they were proposed in a resolution in the General Assembly in December 2016. China, India and Pakistan abstained and North Korea voted in favour. None of the nuclear-armed states or the states protected by the US nuclear umbrella participated in the negotiations. The Netherlands, a NATO country that abstained in the UN vote, was the only nuclear-protected state to participate in the treaty negotiations—and the only state to vote against the final text of the prohibition treaty. Singapore abstained.
This new legal prohibition comes at a time when many experts consider the existing nuclear non-proliferation regime to be in crisis. The cornerstone of this regime is the NPT, which opened for signature in 1968 and entered into force in 1970. It gave the five nations that had exploded a nuclear weapon/device before 1 January 1967 the right to possess nuclear weapons, provided that they commenced negotiations on complete and general nuclear disarmament. The new treaty is a forceful confirmation of article VI of the NPT.
The NPT is reviewed every five years. The final conference document, which is approved by consensus, describes the issues at stake, and proposes future action and reform. The final document of the 2000 Review Conference produced a list of 13 practical steps to be taken. The 2010 Review Conference defined an action plan with 64 actions. The lack of implementation of or concrete results from both documents has been severely criticized. Furthermore, the review conferences in 2005 and 2015 were unable to produce a final document.
There is general agreement that reform of the NPT is needed but no agreement on what form this reform should take. There are two parallel agendas for reform. First, the agenda of Washington and its allies, which seeks to constrain the non-nuclear weapon states by limiting enrichment and reprocessing rights, tightening export controls, imposing more rigorous inspections, and making the need for an Additional Protocol compulsory and withdrawal from the NPT—currently a legal right—impossible.
Second, there is the agenda of the Non-Aligned Movement (NAM), which sees the existing safeguards as satisfactory. These states do not accept limits on technology access and are protective of their right to leave the NPT. In their view, the obligation to disarm must be taken seriously. Despite agreement on the 13 steps in 2000 and the action plan in 2010, the pace of nuclear disarmament has been extremely slow. The path to nuclear disarmament chosen by these states therefore was to focus on the humanitarian consequences of the use of nuclear weapons and start negotiations on a parallel treaty within the UN but outside the context of the NPT.
The Contents of the Ban Treaty
The new treaty prohibits the use or threat of use of nuclear weapons. While the prohibition on use reaffirms international law, the prohibition on the threat of use is an advance.
Furthermore, like the NPT, the treaty prohibits the development, testing, production, manufacturing and other ways of accessing nuclear weapons. The transfer or receipt, as well as the stationing, of nuclear weapons are made illegal, and any assistance or encouragement to do so is not permitted. New issues are introduced, such as victim assistance, environmental remediation and gender-related aspects.
Special procedures have been designed for nuclear weapons states to ratify the treaty as well as those that have nuclear weapons stationed on their soil. All states are expected, as a minimum, to maintain the safeguards standard. In addition, the states parties shall designate a competent international authority (or authorities) to negotiate and verify the irreversible elimination of nuclear programmes and facilities.
Consensus was not possible on a number of issues and many questions were left open, which left many governments feeling disappointed. Issues such as a prohibition on transit or the financing of nuclear weapon programmes were proposed but not explicitly mentioned in the final text, although they were indirectly included in the concept of assistance. The lack of definitions of a nuclear weapon and testing were seen by some states as a problem. Verification was a central issue and many would have liked the IAEA Additional Protocol to be mentioned as a minimum. According to some states, withdrawal from the treaty was also made too easy.
A Hierarchy of Treaties?
The negotiations in New York have polarized the nuclear field. During the work of the Open Ended Working Group, the response by states opposed to a treaty had been labelled ‘the progressive approach’. This underlined the importance of the Conference on Disarmament and assumed a step-by-step process that would include steps such as no-first-use declarations or ratification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). These states expect the new treaty to weaken the NPT by, in their view, creating a parallel structure outside the NPT with a weaker verification regime. The fear is that non-compliant states could hide their intention to develop nuclear weapons.
Some of the non-nuclear weapon states underline the treaty’s complementarity with the NPT and see it as strengthening the NPT. In their view, legally prohibiting nuclear weapons is a repair project that replaces the NPT’s lack of action on nuclear disarmament with a renewed call for the abolition of such weapons.
The frustrated majority among NPT participating states sees the ban treaty as a new legal instrument in its own right. For these states, the original balance between non-proliferation and disarmament in the NPT has been distorted, and the NPT has become a treaty only for non-proliferation. These states are not worried about the minimum verification standard because many of them have not ratified an Additional Protocol.
This polarization has raised the question of whether there will be a hierarchy of treaties. Will the ban treaty supplement or supplant the NPT? Which one will be the fundamental treaty? The relationship is not clearly defined and this will no doubt become the focus once the ban treaty has been ratified and is being implemented.
The Treaty Prohibiting Nuclear Weapons faces a ratification process, according to which 50 states must ratify it before it enters into force. It is hoped that the process will be concluded before the next NPT Review Conference in 2020.
No one expects the nuclear weapon states to abolish their nuclear weapons and ratify the ban treaty any time soon. Nor will the treaty affect their modernization plans currently under way. The treaty is a future-oriented, normative treaty that delegitimizes and stigmatizes nuclear weapons.
Nonetheless, changes are already taking place. The classic argument of NPT supporters that ‘this is the only treaty we have’ no longer holds. Coming nuclear seminars and conferences will have to pay attention to the relationship between the two treaties. Additional pressure will be put on the nuclear weapon states to show progress on disarmament. Civil society has a new instrument at its disposal. The most positive comment, however, came from a young person observing the negotiations in New York: ‘This treaty has really created new energy in the nuclear field’. This is true, and we will all have to wake up.
First published in SIPRI.org
 The five nuclear weapon states under the 1968 Treaty on the Non-proliferation of Nuclear Weapons (Non-proliferation Treaty) are China, France, Russia, the United Kingdom and the United States. Three nuclear weapon possessor states have not signed the treaty: India, Israel and Pakistan. North Korea ratified the treaty but withdrew in 2003.
 Reaching Critical Will, The NPT Action Plan Monitoring Report, March 2015.
 Miller, S., Nuclear Collisions: Discord, Reform and the Nuclear Nonproliferation Regime (Cambridge, MA: American Academy of Arts and Sciences, 2012).
 An Additional Protocol is a legal document that grants the International Atomic Energy Agency (IAEA) additional authority to verify a state’s compliance with its safeguards obligations.
 The Conference on Disarmament is a forum established in 1979 by the international community for its member states to negotiate multilateral arms control and disarmament agreements. The conference negotiated the Biological Weapons Convention and the Chemical Weapons Convention but has for the past 20 years been unable to agree on a work plan for nuclear weapons.