Some good news, for a change: nearly 50 ratifications for the Nuclear Ban Treaty September 24, 2020

PSR is a Partner Organization in ICAN, the International Campaign to Abolish Nuclear Weapons.  ICAN received the Nobel Peace Prize in 2017 for its work leading to the adoption in July, 2017 of the Treaty on the Prohibition of Nuclear Weapons (TPNW).  122 nations adopted the treaty that day, and to date, 84 of them have signed the TPNW. The treaty stipulates that 90 days after the 50th nation ratifies the treaty, it will enter into force.  On September 21, Malta became the 45th nation to ratify the treaty.  ICAN expects at least five additional ratifications before the end of 2020, and once the TPNW enters into force, the legal status of nuclear weapons will change.  It will be a moment that PSR and all the other 570 partner organizations have been looking forward to.

But it is important to realize that the treaty does not directly impact nations (including all nine nuclear-armed countries) that are not yet “party to” the TPNW.  So what will be the significance of entry into force when it occurs?  To answer that question and keep you in-the-know, ICAN staff developed a briefing paper, which we have reproduced in full for you, below.  You can also access the paper as a pdf—with footnotes—here.

“It’s important that we do not overstate what will happen at entry into force. Things will not drastically change on the day it enters into force, because normative impact takes time and requires consistent and constant long-term work. But it’s a significant milestone and will change the legal status of nuclear weapons, and that can have significant concrete impact over time.” 

—  Beatrice Fihn, ICAN Executive Director

The Significance of the Entry Into Force of the Treaty on the Prohibition of Nuclear Weapons

An ICAN Briefing Paper, September 2020


The Treaty on the Prohibition of Nuclear Weapons (TPNW), adopted on 7 July 2017, will enter into force 90 days after the 50th state deposits its instrument of ratification, accession, approval or accession. The entry into force of the TPNW not only triggers states parties’ implementation of the treaty but, as an important milestone in the development of the norm against nuclear weapons, can influence the behavior of states not party, as evidenced by other weapons prohibition treaties.

What is the legal significance of the TPNW’s entry into force?

Once a treaty enters into force, all of its articles apply to all states parties, the countries that have deposited instruments of ratification, acceptance, approval or accession, and thereby agreed to be bound by its articles. For any state that ratifies or accedes to the TPNW after the date on which the 50th instrument of ratification or accession is deposited, entry into force of the treaty for that state will occur 90 days after its ratification or accession. Signatory states are not bound to implement the treaty in the same way that states parties are, but must refrain from violating its object and purpose. Before entry into force, both states parties and signatory states are only bound to refrain from violating the treaty’s object and purpose.

Essentially, entry into force means if a state has joined the treaty, it fully applies to that state. The Treaty on the Prohibition of Nuclear Weapons contains both positive obligations and prohibitions that states parties must implement and abide by upon entry into force, as well as a schedule of meetings for states parties and observers to consider the treaty’s implementation, which will commence within one year of its entry into force.


  • Declarations (Article 2): All states parties must submit a declaration within 30 days of entry into force about its nuclear-weapon status, including if it has nuclear weapons, hosts another states’ nuclear weapons on its territory or has eliminated its nuclear weapons and related facilities.
  • Safeguards (Article 3): All states parties must maintain their current International Atomic Energy Agency (IAEA) safeguards agreement at the time of entry into force and bring into force a comprehensive safeguards agreement at minimum.
  • Elimination and verification (Article 4): Nuclear-armed states that join the treaty must follow one of the treaty’s pathways for the verified elimination of their nuclear weapon programs.
  • Removal (Article 4): Any state party that has nuclear weapons in its territory or any place under its jurisdiction or control that are owned or possessed by another state must remove those weapons.
  • National Implementation (Article 5): All states parties must adopt necessary national measures to implement its obligations under the treaty and to prevent and suppress treaty violations by people or on territory under its jurisdiction or control.
  • Victim Assistance & Environmental Remediation (Article 6): States parties must provide assistance to individuals under their jurisdiction who have been impacted by nuclear weapons use or testing, as well as “take necessary and appropriate measures” towards the environmental remediation of areas under its control contaminated by nuclear weapons use or testing.
  • International Cooperation and Assistance (Article 7): All states parties must cooperate with other states parties to implement the treaty. States parties in a position to do so, as well as states parties that have used and tested nuclear weapons, are obliged to help affected states parties with victim assistance and environmental remediation. States parties may also provide support for the development of national implementation measures and reporting on and destruction of nuclear weapon stockpiles.
  • Universalization (Article 12): All states parties must urge states not party to join.


Article 1 prohibits states parties from developing, testing, producing, manufacturing, transferring, possessing, stockpiling, using or threatening to use nuclear weapons, or allowing nuclear weapons to be stationed on their territory. It also prohibits them from assisting, encouraging or inducing anyone to engage in any of these activities.

Following entry into force of the TPNW, all parties to the treaty will need to take care at all times to ensure that they are complying with all prohibitions under Article 1. Of greatest relevance to most states, especially those with close military ties to nuclear-armed states, is the prohibition on encouraging or assisting another state to engage in a prohibited activity.


Within one year of the TPNW’s entry into force and biennially after that, states parties and observers will convene for a meeting of states parties to consider and take decisions on the treaty’s implementation. At the first meeting of states parties, for example, participants will decide on setting the deadline for the destruction of nuclear weapons for nuclear-armed states who join. The rights of observers will be determined when states parties adopt the rules of procedure at the first meeting of states parties. Five years after entry into force and every six years after that, states parties and observers will convene for a conference to review the treaty’s operation and progress in achieving its purpose. States not party, as well as relevant institutions and non-governmental organizations, can observe the meetings and conferences of states parties of the TPNW after it enters into force.

How will the TPNW’s entry into force impact countries that haven’t joined?

While states not party are not legally bound to abide by the prohibitions and obligations in the treaty, the anti-nuclear-weapon norm strengthened by the TPNW’s entry into force can still shape their behavior and build pressure for their eventual accession. The entry into force of previous weapons prohibitions, including on landmines and cluster munitions, has led to demonstrative changes in adherence to the treaties’ prohibitions and positive obligations by states not party, including the following examples:

  • Production: Since the entry into force of the Convention on Cluster Munitions (CCM) in 2010 and the Mine Ban Treaty (MBT) in 1999, production of the prohibited weapons among states parties and states not party has nearly ceased: three countries are believed to actively produce landmines and ten countries are likely actively producing cluster munitions. Textron and Orbital ATK, two companies producing cluster munitions in the United States, a state not party, have stopped production since the CCM’s entry into force. States not party to the MBT, like Egypt, adopted explicit policies against producing landmines after that treaty’s entry into force.
  • Divestment: Financial institutions often choose not to invest in “controversial weapons,” which are typically weapons prohibited by international law. The entry into force of the TPNW clearly puts nuclear weapons in this category and will likely trigger additional divestment. Following the entry into force of the CCM, the mutual fund Eventide Asset Management, based in the United States, a state not party, excluded cluster munitions from its investments. In addition, states parties may issue directives to financial institutions under their jurisdiction to divest from companies producing the prohibited weapon in states not party to comply with the treaty’s prohibition on assistance with banned activities. In anticipation of the entry into force of the TPNW, some financial institutions, including ABP, one of the five largest pension funds in the world, are already divesting from nuclear weapons producers.
  • Policies against use and transfer: Before the entry into force of the MBT, roughly 34 states exported landmines. Since the entry into force of the MBT, there have been no reported landmine transfers. Very few states not party have used landmines or cluster munitions since the prohibition treaties entered into force. In 2014, the United States, a state not party, announced that it would no longer use landmines outside of the Korean Peninsula, or assist, encourage, or induce other nations to use, stockpile, produce, or transfer antipersonnel mines outside of Korea. The policy was changed under the Trump administration, but more than 100 U.S. members of Congress protested the move in a joint letter. Since the CCM’s entry into force, the United States has only used cluster munitions once, in an isolated 2009 strike in Yemen, and in 2016, it decided to halt transfers of cluster munitions to Saudi Arabia.
  • International cooperation and assistance: The United States is one of the top five donors to support the implementation of MBT obligations, including landmine clearance and victim assistance.

Beyond concrete changes in behavior and policies, the entry into force of the TPNW can advance the stigmitization of nuclear weapons within states not party, including by:

  • Prompting further debates: The treaty’s entry into force could trigger additional discussions within parliaments and media in states not party about the prohibition of nuclear weapons. Already, over 1,600 elected representatives have called on their governments to join the TPNW, as have capitals in nuclear-armed states like Paris and Washington D.C.
  • Institutionalization: The establishment of additional infrastructure to support the treaty’s objectives, such as a conference to promote its universalization, could increase its influence beyond states parties. In addition, as a new legal instrument, the TPNW has already been referenced in multilateral fora that states not party participate in, including the UN General Assembly and meetings of relevant treaties.
  • Impacting alliances: States not party that are in military alliances with states parties may be impacted by the TPNW’s entry into force if the states parties are required to alter their cooperation with nuclear-armed and nuclear-allied states due to their treaty obligations. For example, while members of the NATO alliance may join the TPNW, to be in compliance with its prohibitions once the treaty enters into force, these states will need to renounce the use of nuclear weapons on their behalf. All states parties are also required by the TPNW to encourage states not party to join, including their allies.

Due in part to this mounting political and normative pressure, countries opposing a treaty upon its adoption have joined treaties after their entry into force. Given the overwhelming public support for the TPNW in many countries that have not yet joined it (79% of Australians, 79% of Swedes, 78% of Norwegians, 75% of Japanese, 84% of Finns, 70% of Italians, 68% of Germans, 67% of French, 64% of Belgians and 64.7% of Americans) these countries may also join the TPNW in the years to come.

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