From Division to Constructive Engagement: Europe and the TPNW

December 2021
By Oliver Meier and Maren Vieluf

Europe remains deeply divided over the Treaty on the Prohibition of Nuclear Weapons (TPNW), with NATO membership the main political fault line between treaty critics and sympathizers. Since 2010, NATO has described itself as a nuclear alliance. In December 2020, all 30 of its members collectively stated their opposition to the ban treaty, but that appearance of unity is vanishing as the treaty picks up support in key allied nations.

Norwegian Prime Minister Jonas Gahr Store (R), shown hosting German President Frank-Walter Steinmeier in Oslo. Both countries recently announced that they will attend the first meeting of the states-parties of the Treaty on the Prohibition of Nuclear Weapons (TPNW) as observers in March 2022. (Photo by Håkon Mosvold Larsen / NTB / AFP via Getty Images)The 27 EU members, by contrast, have agreed to disagree on the TPNW. Three EU states are parties to the TPNW, while France, the only EU nuclear-weapon state, remains a staunch opponent. The other European states linger somewhere between these positions.

This disunity reduces European influence on the nuclear disarmament debate. In the past, when it acted jointly, the European Union was often able to facilitate global agreement on steps to reduce the role and number of nuclear weapons. The union has been a key force in shaping the multilateral arms control, disarmament and nonproliferation landscape. NATO, the EU, and Europeans could again assume such roles by constructively engaging with the ban treaty.

In this sense, the treaty is an opportunity, rather than an obstacle, to increase European agency on the way toward a world free of nuclear weapons.

So how can NATO, the EU, and European nations make the best use of the TPNW in striving toward nuclear disarmament? What options exist for EU and NATO members to reduce divisions over the treaty and build on the momentum it has created while respecting each other’s viewpoints? These questions are particularly acute as NATO revises its Strategic Concept and Europeans prepare for the 2022 Nuclear Nonproliferation Treaty (NPT) Review Conference in New York on January 4–28 and the first meeting of TPNW states-parties, which will take place in Vienna on March 22–24.

NATO’s Crumbling Unity

Until recently, NATO members collectively opposed the ban treaty. In the waning days of the Trump administration, the alliance argued that the TPNW “risks undermining the global non-proliferation and disarmament architecture” and called on “partners and all other countries to reflect realistically on the ban treaty’s impact on international peace and security.”1

In mid-October 2021, however, the newly elected Norwegian government, led by Prime Minister Jonas Gahr Støre, tore down the façade of unity by announcing its intention to attend the first meeting of the TPNW states-parties as an observer.2

In Germany, the parties in the new government pledged in their November 24 coalition agreement that Berlin would observe “in close consultation” with allies the first meeting of TPNW states-parties “in order to constructively accompany the intentions of the treaty.”

NATO’s hard-line stance against the treaty has stood on shaky ground for some time. In Spain, government coalition partners in 2018 informally agreed to join the treaty, although they subsequently failed to act on that commitment. The Dutch Parliament forced the government to take part in the 2017 UN General Assembly negotiations on the ban treaty. The Belgian government in 2020 pledged to explore how the treaty “can give new impetus to multilateral nuclear disarmament.”3 Thus, three of the five states that host U.S. nuclear weapons under NATO's nuclear sharing arrangements—Belgium, Germany, and the Netherlands—have struggled to stay faithful to the alliance position on the ban treaty.

French President Emmanuel Macron, shown at a NATO meeting in June in Brussels, has been leading the charge to keep the alliance from joining the Treaty on the Prohibition of Nuclear Weapons (TPNW). (Photo by THOMAS COEX/AFP via Getty Images)All of this is unlikely to sway treaty opponents. Paris is leading the charge. In a speech on French nuclear policy on February 7, 2020, French President Emmanuel Macron accused “advocates of abolition” of attacking the legitimacy of nuclear deterrence “where it is easiest, that is to say in…European democracies.”4 France is the only NATO state not participating in the alliance’s Nuclear Planning Group and its integrated nuclear policies. From its position of “splendid isolation” on nuclear issues within NATO, Paris has repeatedly vetoed progress on nuclear arms control and disarmament and is likely to remain adamantly opposed to any engagement with the ban treaty.5

As so often in NATO, in the end it will be the U.S. position that makes the difference. The Biden administration, however, has not indicated whether it intends to move away from the strong treaty opposition of his two immediate predecessors. A change of policy would require a step away from Biden’s past positions. In 2016, while Biden was vice president in the Obama administration, Washington had urged allies to reject any initiative to negotiate a treaty banning nuclear weapons. In an October 2016 nonpaper sent to the North Atlantic Council, NATO’s political decision-making body, even before treaty negotiations started in 2017, Washington warned that nuclear burden-sharing “could become untenable” and alliance consensus on the deterrence “could splinter” if any NATO member decided to join a ban treaty.6

The alliance is now struggling to square its rigid opposition to the treaty with changing political realities. When asked about his reaction to Oslo’s decision to observe the TPNW states-parties meeting, NATO Secretary-General Jens Stoltenberg, a Social Democrat like Støre and also a former Norwegian prime minister, replied that he expects allies to take NATO’s opposition to the treaty into account when addressing nuclear issues and that they should “consult closely with other NATO allies.”7

Stoltenberg made the remarks on the sidelines of a NATO defense ministers meeting in October that preceded a meeting of the Nuclear Planning Group, where ministers discussed the treaty issue. Stoltenberg’s chief of staff, Stian Jenssen, in an October 27 op-ed in the Norwegian newspaper VG warned that if Norway signs the TPNW, “it will endanger a wide range of defense and security policy cooperation with our closest allies.”8 So far, Oslo appears to be resisting peer pressure.

A Union Divided

Although NATO has worked hard to project unity on nuclear disarmament, the EU has effectively conceded failure.9 The breaking point came in 2015, two years before 122 states adopted the TPNW in the UN General Assembly. In 2013 and 2014, most EU member states had attended international conferences on the humanitarian and environmental impact of nuclear weapons in Oslo; Nayarit, Mexico; and Vienna. Nuclear-weapon state France shunned all three conferences. Reflecting this split, EU members failed to reach consensus on nuclear disarmament language for the 2015 NPT Review Conference. For the first time, in such a common decision, Europeans could only acknowledge their internal split by noting “the ongoing discussions on the consequences of nuclear weapons, in the course of which different views are being expressed, including at an international conference organized by Austria, in which not all EU Member States participated.”10

As discussions on a treaty prohibiting nuclear weapons moved ahead, this gap deepened, while support for the ban treaty globally as well as among Europeans grew broader. Many European non-nuclear-weapon states participated in a 2016 open-ended working group set up by the UN General Assembly to “take forward” multilateral nuclear disarmament negotiations. Yet, most EU and NATO members voted against a December 2016 UN resolution recommending full-fledged negotiations on a nuclear weapons prohibition treaty, even though the European Parliament had passed a resolution welcoming the ban treaty and calling on EU member states to support and “participate constructively” in the talks.11

In the end, many EU members stayed away from the 2017 UN General Assembly negotiations on the ban treaty. From Europe, only non-NATO members Austria, Cyprus, Ireland, Malta, and Sweden eventually voted for the legally binding TPNW, which comprehensively prohibits nuclear weapons. NATO member the Netherlands was the only state to vote against adoption of the ban treaty. Austria and Ireland, who are leading promoters of the treaty, and Malta are the only EU members among the 56 TPNW states-parties.

Another complication is that parliaments in many European countries and the European Parliament itself tend to be more open toward engagement with the TPNW than their governments. On October 21, the European Parliament issued a recommendation that referenced the security context and supported a step-by-step approach to nuclear disarmament but also recognized the TPNW as an expression of discontent by a majority of states with international disarmament efforts.12 Because the EU position remains fragmented along multiple lines, reaching a unified European position on the TPNW is likely to remain difficult.

Action Out of Diversity

Any future European policy on the treaty will have to take into account the broad spectrum of views on nuclear weapons that NATO and EU member states represent, with seemingly irreconcilable differences between the extremes. Although the TPNW has brought these divergences to light, it is not their root cause. Rather, they can be traced to different interests, cultures, historical experiences, and alliance relationships among European states. Differences also exist at the domestic level, as demonstrated by ongoing debates on national nuclear disarmament policies even in countries whose governments have charted a clear course against the TPNW.

Efforts to address European divisions on the TPNW and on nuclear weapons more generally will be arduous, but they are necessary to mitigate the counterproductive consequences of the European disputes and paralysis. For example, European engagement with a growing number of states supportive of the TPNW and the new ban treaty regime is a key to preserving Europe’s global role as an advocate of multilateralism. Europe is the region most opposed to the nuclear weapons ban. Of the 42 countries that reject the ban treaty, 31 are European nations. Europe’s legitimacy as a disarmament advocate depends on its ability to speak to ban treaty supporters and particularly the 86 countries that have signed or ratified the ban treaty.13

Europeans also need to find a more productive position toward the treaty if they want to reduce the risk of a widening rift among NPT member states on nuclear disarmament, which is a declared goal of the EU.

Meanwhile, NATO’s denunciation of the treaty is at odds with domestic developments in a number of key European countries. As an alliance of democracies, NATO should be responsive to such political shifts among its members and accommodate the momentum toward the TPNW. Unity has never been and cannot be based on demands to adhere to previously agreed positions when the context has changed.

Finally, European engagement is important for the treaty’s evolution. Many Europeans and NATO members criticize the TPNW’s verification provisions as too weak. They also argue that the treaty could undermine the NPT by establishing a competing legal and normative framework. Yet, the TPNW entered into force on January 22, 2021, and it is here to stay. If European critics want their concerns about the treaty to be addressed, they need to sit at the table. Staying on the political sidelines takes Europeans out of the nuclear disarmament game, so
how can Europeans engage constructively with the treaty through NATO, the EU, and individually?

Adjusting NATO's Policy

To maintain NATO unity, allies should agree on a more sustainable and forward-looking policy on the treaty. The current approach of completely rejecting the TPNW confronts members who are willing to recognize the treaty as a useful addition to the disarmament toolbox with an impossible choice. States such as Norway either can bow to pressures from the nuclear-weapon states and grudgingly step back into line or would have to break ranks with the alliance. For NATO, which is built on solidarity and rightly prides itself on being a political institution as well as a military alliance, such strongman tactics would be counterproductive.

At least implicitly, the alliance should acknowledge that engagement with the treaty, including attendance at TPNW meetings, does not weaken NATO coherence on nuclear matters, just like Dutch participation in the treaty negotiations had no discernible impact on perceptions of NATO unity or the effectiveness of NATO’s nuclear posture.

One opportunity to adjust NATO’s nuclear disarmament policies to political realities are discussions on a new strategic concept, to be agreed by the next alliance summit in Spain in the summer of 2022. Allies launched that process at their June 2021 summit in Brussels, when they confirmed their intention “to take all necessary steps” to maintain a credible deterrence posture but also committed to “support and strengthen arms control, disarmament, and non-proliferation.”14

In the new strategic concept, NATO could acknowledge the ban treaty as a good faith effort by the majority of states to eliminate the nuclear danger and build up the legal framework for the elimination of nuclear weapons.15 Such a statement would stop well short of support for the nuclear weapons prohibition as a generally accepted international norm.

Collectively and individually, NATO allies have persistently objected to the “argument that the TPNW reflects or in any way contributes to the development of customary international law.”16 Engagement with the treaty, including observing meetings of TPNW states-parties, can be consistent with such a policy if the allies continue to point out the substantive reasons for not acceding to the TPNW. For example, Israel, which possesses nuclear weapons, has observed several NPT review conferences and in 2015 submitted a working paper even though it does not want to join that treaty and nobody would expect that.

NATO could also engage with the TPNW by being more transparent about how it wants to ensure its nuclear planning is consistent with international humanitarian law. Scott Sagan and Allen Weiner have analyzed how the United States goes to great lengths to ensure that its nuclear war plans are consistent with these laws.17 They describe the procedures by which U.S. governments seeks legal advice so they follow international legal guidelines when developing nuclear war-fighting scenarios and preparing rules for nuclear weapons use. Naturally, nobody would expect NATO to discuss nuclear targeting plans. Yet, the alliance could describe the processes by which it implements its international humanitarian law obligations, including at which points and through which institutions allies individually can have an impact on such plans and their possible implementation in case of war.


Getting the EU’s Act Together

The 27 EU member states have been tiptoeing around their TPNW differences. Their foreign ministers on November 15 adopted a common position for the NPT review conference. The conclusions of the Council of the European Union do not even mention the ban treaty and merely note “the very severe consequences associated with nuclear weapons use”, while emphasizing “that all States share the responsibility to prevent such an occurrence from happening.”18

This lowest common denominator agreement does not put Europe in a position to shape discussions on nuclear disarmament. High-level engagement by European leaders will likely be needed to develop a more nuanced position. Such a stance could identify areas of agreement, along with those areas where Europeans continue to disagree or where they would push ban treaty supporters for further clarification. The difficult quest for greater convergence on nuclear disarmament is also mandated by the Treaty on the European Union, which calls on member states to “coordinate their action in international organizations and at international conferences.”19 More importantly, such a graded position on nuclear disarmament would help improve the credentials of the EU as a bridge-builder within the global nonproliferation regime.

At the review conference, the EU and member states should seek to reduce polarization over the TPNW by promoting language that recognizes the entry into force of the treaty and acknowledges the different perspectives on it. As Spanish analyst Clara Portela has emphasized, “Recognising the legitimacy of the treaty objectives does not equate to sympathising with the treaty, let alone to adhering to it.”20

The EU could also be a champion for those issues that are widely perceived as common ground among the nuclear disarmament camps. Thus, on nuclear risk reduction, Europeans could endorse a restatement by NPT states-parties of the Reagan-Gorbachev formula that “a nuclear war cannot be won and must never be fought.” Highlighting the importance of transparency as a method of fostering nuclear disarmament is another way in which Europeans can bolster the disarmament agenda, while enlarging the middle ground among NPT states-parties.

Looking beyond the review conference, the EU could seek to link the intersessional processes under the NPT and TPNW. Politically, this should be unproblematic as long as TPNW membership remains a subset of NPT membership. For example, NPT states-parties could invite the chairs of TPNW meetings of states-parties to issue formal reports at subsequent NPT preparatory committee meetings and at the 2025 NPT Review Conference. The EU could also propose that NPT states-parties establish an open-ended working group on ways and means to better integrate humanitarian law in nuclear weapons-related security concepts.21

The choice of Europe as the venue for the first TPNW meeting of states-parties places a special responsibility on Europeans to make the meeting a success. The EU itself could apply to observe the meeting as a relevant international or regional organization. The fact that the ban treaty remains contested must not be an insurmountable hurdle. The European Commission and the EU have observed the first meetings of states-parties to other treaties, even though at the time only some EU member states were parties.22

The European Parliament, which remains divided on the ban treaty, has not decided whether to send a delegation to the TPNW meeting, but the parliament’s Left and Green parliamentary groups will be represented. They also have asked the EU special envoy for nonproliferation and disarmament to represent the EU at the meeting as an observer regional organization.23 EU members Germany, Finland, and Sweden have already stated their intention to observe the meeting,24 and others might and should follow their lead.

Looking beyond the Vienna meeting, the EU could facilitate implementation of TPNW provisions on victim assistance and environmental remediation. France and the United Kingdom conducted all their nuclear weapons tests outside their European home territories and have a special responsibility to address the consequences of their nuclear weapons programs for humans and the environment. Such support would flow from the EU’s stated goal to “strongly support” the full implementation of multilateral disarmament, nonproliferation, and arms control treaties.25

The European Parliament could strengthen its role as a forum for diverse viewpoints on nuclear disarmament. It could seek to address the tension between deterrence and disarmament in a series of hearings involving both TPNW supporters and critics. The parliament could invite France and other NATO allies to explain how the alliance will ensure that nuclear planning takes into account international humanitarian law requirements to reduce human suffering in conflict. This could involve further discussion on whether any use of nuclear weapon is incompatible with international humanitarian law, as TPNW supporters argue.

Furthermore, the parliament could build on its traditional strength of using parliamentary diplomacy to influence the EU foreign and security policy agenda. For example, the parliament’s delegation to the NATO Parliamentary Assembly could use the results of hearings on the TPNW to initiate debate within the assembly. Such interaction could also help to broaden NATO-EU relations, which are now focused on defense issues, to include a common strategic culture on arms control, disarmament, and nonproliferation.

Participation of individual countries as observers in TPNW meetings is key. According to the Treaty on the European Union, states participating in international organizations and at international conferences shall uphold EU positions. A common EU approach toward the TPNW, as outlined above, would thus strengthen Brussels’ voice at the Vienna conference and other ban treaty gatherings.

In the end, Europeans need to change their perspective. Ban treaty supporters need to acknowledge the position of those who support nuclear deterrence. TPNW critics should view the ban treaty not as a problem, but as an opportunity to make progress toward reducing the role and number of nuclear weapons. Through a policy of constructive engagement with the TPNW, Europe can address its long-standing ambiguity on the role of nuclear weapons and strengthen European agency in nuclear disarmament. That would be good for Europe and, more importantly, for nuclear disarmament in general.



1. NATO, “North Atlantic Council Statement as the Treaty on the Prohibition of Nuclear Weapons Enters Into Force,” press release (2020) 131, December 15, 2017,

2. Alf Bjarne Johnsen and Gisle Oddstad, “Støre-Regjeringen Reiser Til Atomforbud-Konferanse: USA Stiller Spørsmål” [Støre government travels to nuclear ban conference: U.S. asks questions], VG, October 14, 2021,

3. Government of Belgium, “Accord de Gouvernement” [Government agreement], September 30, 2020, p. 78,

4. Emmanuel Macron, “Speech of the President of the Republic on the Defense and Deterrence Strategy,” February 7, 2020,

5. Oliver Meier and Simon Lunn, “Trapped: NATO, Russia, and the Problem of Tactical Nuclear Weapons,” Arms Control Today, January 2014, pp. 18–24,

6. NATO, “United States Non-Paper: ‘Defense Impacts of Potential United Nations General Assembly Nuclear Weapons Ban Treaty; Note by the Secretary,’” AC/333-N(2016)0029 (INV), October 17, 2016.

7. NATO, “Doorstep Statement by NATO Secretary General Jens Stoltenberg Ahead of the Meetings of NATO Defence Ministers on 21 and 22 October at NATO Headquarters,” October 21, 2021,

8. Stian Jenssen, “Veien Mot En Verden Uten Atomvåpen” [The road to a world without nuclear weapons], VG, October 27, 2021,

9. The EU-related section of this article draws heavily on Tytti Erästö et al., “A Fresh Breeze for Nuclear Disarmament in Europe? Making Best Use of the Treaty on the Prohibition of Nuclear Weapons,” The Greens/EFA in the European Parliament, June 2021,

10. Council of the European Union, “Council Conclusions on the Ninth Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons,” No. 8079/15, April 20, 2015.

11. European Parliament, “European Parliament Resolution of 27 October 2016 on Nuclear Security and Non-Proliferation (2016/2936(RSP)),” October 27, 2016.

12. European Parliament, “Recommendation to the VPC/HR and to the Council in Preparation of the 10th Non-Proliferation of Nuclear Weapons Treaty (NPT) Review Process, Nuclear Arms Control and Nuclear Disarmament Options (P9_TA(2020)028),” October 21, 2020.

13. On the current status of support of the TPNW, see Nuclear Weapons Ban Monitor, (accessed November 13, 2021).

14. NATO, “Brussels Summit Communiqué Issued by the Heads of State and Government Participating in the Meeting of the North Atlantic Council in Brussels 14 June 2021,” June 14, 2021, (hereinafter “NATO Brussels summit communiqué”).

15. Daryl G. Kimball, “The Nuclear Ban Treaty: A Much-Needed Wake-Up Call,” Arms Control Today, November 2020, p. 3,

16. NATO Brussels summit communiqué.

17. Scott D. Sagan and Allen S. Weiner, “The Rule of Law and the Role of Strategy in U.S. Nuclear Doctrine,” International Security, Vol. 45, No. 4 (Spring 2021): 126–166.

18. Council of the European Union, “Council Conclusions on the 10th Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT),” 13243/21, November 15, 2021.

19. Treaty of the European Union, art. 34.

20. Clara Portela, “The EU’s Arms Control Challenge: Bridging Nuclear Divides,” Chaillot Paper, No. 166, April 2021,

21. See Thilo Marauhn, “Reducing the Role of Nuclear Weapons: A Role for International Law,” in Meeting in the Middle: Opportunities for Progress on Disarmament in the NPT, King’s College London Centre for Science and Security Studies, December 2019, pp. 34–37,

22. See Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-Personnel Mines and on Their Destruction, 2056 U.N.T.S. 211, September 18, 1997; Diplomatic Conference for the Adoption of a Convention on Cluster Munitions, “Convention on Cluster Munitions,” CCM/77, May 30, 2008.

23. Mounir Satouri (@MounirSatouri), “Together with fellow MEPs @Oezlemademirel @Brandobenifei and @Lukasmandl we will attend the First meeting of the #TPNW We Call on the @EUCOUNCIL to mandate the EU special envoy to attend #1MSP #nuclearban,” Twitter, September 7, 2021, 12:05 p.m.,

24. Ann Linde, “Statement of Foreign Policy 2021,” Swedish Ministry of Foreign Affairs, February 24, 2021,; Pekka Haavisto, “Speech by Pekka Haavisto, Minister for Foreign Affairs, at the Meeting of Heads of Mission, 23 August 2021,” Ministry of Foreign Affairs of Finland, August 23, 2021, German Coalition Agreement, 2021.

25. European Union, “Shared Vision, Common Action: A Stronger Europe; A Global Strategy for the European Union’s Foreign and Security Policy,” June 2016, pp. 41–42,

Oliver Meier is a senior researcher in the Berlin office of the Institute for Peace Research and Security Policy at the University of Hamburg (IFSH). Maren Vieluf is a researcher in the Challenges to Deep Cuts Project in the Berlin office of IFSH.