Options for a Peace Settlement for Ukraine: Option Paper I – Neutrality and Related Concepts

Options for a Peace Settlement for Ukraine: Option Paper I – Neutrality and Related Concepts

[Marc Weller is Professor of International Law and International Constitutional Studies in the University of Cambridge, the former Director of the Lauterpacht Centre for International Law and of the European Centre for Minority Issues, a former United Nations Senior Mediation Expert and a Barrister (Middle Temple) at Doughty Street Chambers. He served as advisor in a large number of international peace negotiations. He is the co-editor of International Law and Peace Settlements, Cambridge University Press, 2021. The views expressed are his own alone.]

A previous contribution to Opinio Juris considered what a possible settlement for Ukraine might look like. The aim was to show that a relatively condensed settlement could be possible, despite the ever more complex nature of the situation in Ukraine. That contribution also attempted to demonstrate a few ideas on how one might address some of the more difficult issue areas in a potential settlement.

Any specific settlement proposal will of necessity reflect the relative configuration of the sides on the battlefield and in the wider political arena. It is not possible to predict what this situation will be by the time the sides come to an eventual settlement. However, the parties and, when it comes to that, the mediators, might find it helpful to see a fairly broad range of options for addressing each of the key issue areas they will face when constructing the actual settlement.

To help meet this need, we have established a Ukraine Peace Settlement Initiative in the University of Cambridge, in collaboration with the Harvard Negotiation Project and Opinio Juris. We will offer settlement options on most of the core issues for the sides. The first few have been authored by Professor Marc Weller. A significant range of other authors will add additional pieces to the puzzle over the coming weeks.

A collection of all option papers and of other helpful materials relating to a possible settlement of the conflict will be made available on its own, dedicated web-site shortly.

This first options paper addresses the status of Ukraine, in particular possible neutrality. An accompanying options paper, the next in the series, will consider Security Guarantees—an issue raised by Ukraine in connection with the question of possible neutrality.We are grateful to Opinio Juris for agreeing to serve as project partner, offering a broader exposure to the option papers as they appear.


Introduction: The Issue of Neutrality in the Negotiations

In a much noted speech at the Munich Security Conference of 2007, the President of the Russian Federation, Vladimir Putin, protested against the positioning by NATO of its ‘frontline forces on our borders.’ He considered this act a ‘serious provocation.’

Nevertheless, in April of 2008, the Bucharest NATO summit opened the prospect of NATO membership for Ukraine (and Georgia):

NATO welcomes Ukraine’s and Georgia’s Euro-Atlantic aspirations for membership in NATO.  We agreed today that these countries will become members of NATO.  Both nations have made valuable contributions to Alliance operations. [para 24.]

In the wake of the 2008 Russia’s military operation in South Ossetia and also Abkhasisa, then President of Russia, Dmitry Medvedew, put forward a proposal for a new European security order, which sought to exclude NATO expansion. That proposal was later supplemented by a draft treaty presented by the Russian Federation of November 2009, which would have put an ‘end to NATO’s eastward enlargement.’ [p. 8.]

On 17 December 2021, as its armed forces started to assemble on the borders of Ukraine, the Russian Federation re-issued a proposal for a European Security Order. Article 4 of the proposal provided:

The United States of America shall undertake to prevent further eastward expansion of the North Atlantic Treaty Organization and deny accession to the Alliance to the States of the former Union of Soviet Socialist Republics.

The United States of America shall not establish military bases in the territory of the States of the former Union of Soviet Socialist Republics that are not members of the North Atlantic Treaty Organization, use their infrastructure for any military activities or develop bilateral military cooperation with them.

A second draft agreement accompanying the first, provided, also in its Article 4:

The Russian Federation and all the Parties that were member States of the North Atlantic Treaty Organization as of 27 May 1997, respectively, shall not deploy military forces and weaponry on the territory of any of the other States in Europe in addition to the forces stationed on that territory as of 27 May 1997. With the consent of all the Parties such deployments can take place in exceptional cases to eliminate a threat to security of one or more Parties.

The US and NATO rejected these proposals, confirming that the ‘open door policy’ of the alliance would remain. As the present conflict erupted, the Russian Federation repeatedly alluded to NATO’s failures to address Russian security concerns relating to NATO expansion as one of the reasons for its ‘special military operation.’

When President Putin expressed his conditions for a peace settlement, neutrality for Ukraine was reportedly the first requirement he raised. By that time, President Volodomir Zelensky had already hinted at the willingness of Ukraine to consider neutrality, if balanced by security guarantees and supported in a referendum. The Russian Federation indicated its willingness to address this proposal in direct negotiations, initially taking place in Turkey on 29 March 2020.  Indeed, Russia announced a reduction in its armed activities in Western Ukraine in view of this perceived concession.

This Options Paper will consider

  • Option 1: Permanent Neutrality
  • Option 2: An Undertaking not to join NATO
  • Option 3: Non-aligned Status
  • Option 4: The issue of the EU

Option 1: Permanent Neutrality

A. Meaning of Neutrality

Neutrality consists of an undertaking by a state not to assist any side in a present or future armed conflict (or traditionally, war). This includes several elements.

First, and most obviously, the neutralized state must not participate in an armed action prosecuted by another state. It must not offer military assistance, basing rights, refuelling of communication facilities, or other support.

A neutral state may, on the other hand, provide humanitarian assistance, offered to both sides in the conflict and delivered according to need alone. It is perhaps no accident that the International Committee of the Red Cross, while in principle a private association, is nevertheless based in neutral Switzerland.

Second, a neutral state cannot participate in a defensive alliance. An alliance would bind the neutral state to the defence of other participants in the defensive arrangement in case of an armed attack (e.g., the famous Article 5 commitment of the NATO Treaty). The neutral state may also not offer military bases or other facilities to foreign states or alliances.

For instance, the constitutional act of Austria of 1955 establishes that ‘in all future times Austria will not join any military alliances and will not permit the establishment of any foreign military bases on her territory.’ [Constitutional Law on Neutrality, 26 October 1955, Article 1 (ii)].

It is not necessarily clear that permanent neutrality would exclude partnership arrangements between NATO and Ukraine, although it is likely that the Russian Federation might insist on such a provision.

In any event, neutrality does not exclude external support in developing the defensive capacity of the state concerned, whether provided by individual states or by organizations. This includes provisions of arms and training, but might exclude participation in integrated defensive arrangements and possibly joint manoeuvres.

At the round of talks between the sides in Turkey of 29 March, Ukraine appears to have accepted that there would be no joint training exercises with other forces in Ukraine other than with the specific consent of the Russian Federation

While a neutral state cannot be a member of an alliance, dedicated to the collective defense of whichever state suffers an armed attack, it can nevertheless benefit from security arrangements. After all, neutrality can be guaranteed by third states. That is to say, the third states pledge to defend the permanently neutral state should it becomes subject to an aggression in disregard of its neutral status. The United Kingdom entered World War I in fulfilment of its guarantee of Belgian neutrality under the Treaty of London of 1939—a historical fact to be borne in mind when considering the related issue of security guarantees.

B. The Obligation to Defend the Territory Effectively

The permanently neutral state must ensure that its territory is not used as a basis, or to the advantage of, a party to the conflict. That means that it needs to be able credibly to defend its neutrality against a state trying to occupy the territory, to use it as a deployment area, or to march through it when attacking a third state. Germany occupied neutral Norway in World War II, arguing it had to do so to forestall it coming under the control of one of her enemy states. Norway refused to capitulate and attempted to assert its neutrality through armed resistance.

Similarly, in World War I, Germany demanded that Belgium should permit a German assault on France through Belgian territory. Again, Belgium attempted to defend its neutrality, also bringing the UK, a guarantor state, into the war. In more modern practice, this commitment to ‘armed’ neutrality and effective defense of the territory is reflected in Article 1 (i) of the Austrian constitutional law noted above.

Hence, permanent neutrality may not be fully consistent with a further demand put forward by the Russian Federation—that of the disarmament of Ukraine. To the contrary, under permanent neutrality Ukraine would be obliged to maintain a significant military capacity, demonstrating its capacity to preserve and defend its neutrality under all circumstances.

This fact suggests that any arms limitation provisions agreed for Ukraine would need to be fairly limited. They might be restricted to permanently removing the option of acquiring weapons of mass destruction and limiting numbers of missiles and cruise missiles above a certain range. Other restrictions of force numbers, heavy weapons, armour and air and naval units could only be contemplated at a level that is consistent with an effective defence of the territory.

In the alternative, if permanent neutrality is to be combined with more significant disarmament, then third states would need to undertake the obligation to ensure the effective defense of the territory—an issue addressed in the next Options paper.

C. Neutrality and Collective Security

This classical view of neutrality has been challenged with the advent of the UN Charter, and in particular since the end of the Cold War. Switzerland, for instance, refused to join the United Nations for many decades. It feared that the obligation to comply with Chapter VII decisions of the Security Council under Articles 24 and 25 of the Charter might push it into an obligation to violate, either its obligations as a permanently neutral state, or its obligations under the UN Charter. Switzerland did eventually join in 2002.

This dilemma arose in a somewhat different form for Germany in the Wimbledon case before the Permanent Court of International Justice. [PCIJ, Ser.  A, No. 1 (1923).] The question in that case was whether Germany could stop vessels carrying armaments, munitions and other contraband aimed for a party to a conflict, from traversing the Kiel Canal. Germany argued that it had to stop such passage in line with its position of neutrality in the conflict. The Kiel Canal connects the North Sea and the Baltic. Under the Treaty of Versailles, Germany was obliged to keep the canal open to vessels of all nations under all circumstances.

The Court ruled that Germany was obliged to comply with its obligations under the Treaty of Versailles—a treaty establishing obligations with respect to the Canal that all states of the world were entitled to rely on–even if this might potentially mean violating neutrality. Hence other legal obligations owed to the international community as a whole may trump neutrality.

With the advent of the UN Charter, the question is whether a neutral state can evade the obligation to adopt enforcement action against an aggressor so identified by the UN Security Council. If it has to adopt enforcement action, would this not constitute an unneutral act towards the transgressor?

On the other hand, if the system of collective security specifically and authoritatively identifies the aggressor state and the victim state, neutrality may lose its meaning. Assisting the victim of the aggression may be an obligation under Chapter VII of the Charter and possibly even under general international law. It may appear as an unneutral act to the transgressor, but within the modern system of collective security, if it operates as intended, there is an argument that there can be no neutrality vis-à-vis an aggressive war.

Hence, if neutrality precludes membership in a collective self-defence arrangement, or alliance like NATO, it does not exclude membership in a collective security organization like the UN. As Sweden’s or Switzerland’s participation in the United Nations demonstrates, neutrality and collective security are not incompatible. The same applies to membership in relation or sub-regional collective security organizations or arrangements.

In cases of supranational organizations, like the EU, neutral states have been able to negotiate special arrangements where the collective security dimension is concerned. (Article 42 (7), Treaty of the European Union, see Option 4 below).

D. Establishing Permanent Neutrality

The Russian Federation is demanding that the status of Ukraine it seeks must be anchored in legally binding undertakings. Permanent neutrality can be established in the following ways:

International Systemic Settlement: The obligation may be part of a larger, global constitutional settlement among many key states. Examples include neutral Switzerland at the Congress of Vienna 1815 and Belgium at the London Conference of 1939.

Specialist Treaty: Permanent neutrality could be anchored in a treaty among a small number of states. In that case, the treaty is likely to have been specifically concluded to address the neutral status of the entity in question and possibly to provide a guarantee of that status, or the issue may be included in the overall peace settlement agreement. An example, in a somewhat different context, is the four-power treaty of guarantee concerning Cyprus, concluded in 1960 between Cyprus, Greece, Turkey and the UK. That treaty was meant to guarantee the status of Cyprus as an independent state (rather than joining Greece).

Recognition of Status: The state concerned will issue a declaration concerning its future status. It is then recognized as permanently neutral by other states, confirming the obligation undertaken by the neutral state. This recognition can take the form of a collective act, for instance by means of a General Assembly Resolution, as occurred when Turkmenistan became a member of the United Nations.

Security Council Anchoring: The status of Ukraine could be anchored in a binding, Chapter VII resolution of the UN Security Council. Such a provision could then only be changed with the affirmative vote of the Russian Federation as a permanent member. More likely, the entire settlement agreement would presumably be endorsed by the Council. That endorsement could be phrased in a way which could result in a similar effect.

Constitutional Anchoring:  Neutrality can be anchored in the state constitution. This can take the form of a commitment to permanent neutrality in the state constitution itself, as in Moldova. Or it can take the form of a parliamentary declaration of constitutional standing, as was the case in Austria, immediately upon completion of the withdrawal of Soviet forces from its territory under the 1955 Austrian State Treaty. Interestingly for the present context, that declaration was clearly connected with the completion of the Soviet withdrawal from Austria, but was presented as a ‘permanent neutrality of its [Austria’s] own accord.’

Unilateral Declaration: The obligation to maintain neutrality becomes legally binding by virtue of a solemn declaration by the President or Head of Government directed at the world at large (Sweden in 1834). In international law, such declarations are binding erga omnes, and all other states can legally rely on the declaration. A more recent example of a unilateral status declaration is the Declaration of Independence of Kosovo of 2008. While not imposing neutrality, the declaration commits Kosovo in a legally binding way to full compliance with the terms of a UN Comprehensive Settlement Proposal for Kosovo.  

Informal Policy: Finally, a state can announce itself to be neutral, without engaging in a binding legal obligation to that effect. The declaration concerned would be an announcement of a certain policy, and not a manifestation of an obligation in international law (Finland).

E. How Permanent is Permanent

Nothing in life is permanent. Does this also apply to permanent neutrality? Depending on the mechanisms noted above, some of the the arrangements provided can be changed over time. They critical element, however, is that such a change would need to take place in accordance with international law or, as the case may be, national legislation or constitutional law.

State legislation: Starting with the latter, if permanent neutrality is anchored in state legislation, it can be changed by the same majority required for the adoption of the relevant law. For instance, in December 2014, in the wake of the initial military operation by the Russian Federation relative to Ukraine, 303 out of 450 members of the Ukrainian parliament voted to remove the provisions of the law on foreign relations that provided for non-alignment. That law had been adopted under the predecessor government of Viktor Yanukovych.

Constitution: If permanent neutrality is anchored in the state constitution, the relevant provision can only be amended or removed by the majority required for a constitutional change. At present, the Ukrainian Constitution requires a 2/3rds majority. However, additional safeguards for qualified voting might be introduced in relation to particular provisions of the constitution. For instance, there might be a double majority provision, requiring a majority within the parliament overall, plus a majority, or qualified majority, from among a nominated ethnic or linguistic or regional constituency within the parliament.

Permanence Clause in the Constitution: Another solution would be a permanence clause that removes the option of amending or removing certain provisions from a constitution (as is the case in Germany’s constitution). The only way to overturn a provision thus protected would be through a revolutionary change that would abolish the existing constitution altogether.

Treaty Commitment: A neutrality undertaking can be established in the settlement treaty. In that case, it is evidently important to ensure that the instrument in question is actually a formal treaty eligible for registration with the UN Secretariat. A treaty obligation can only be impeached in accordance with the provisions of the Vienna Convention on the Law of Treaties (unless the other treaty parties agree to a change). These provisions are narrowly framed in favour of preserving treaty obligations even if political or other circumstances change. The principal exception concerns a fundamental and unforeseen change of circumstance relating to the essential basis of the consent to be bound by the obligation radically transforming the obligation in question, or a material breach of the treaty in question.

Unilateral Declaration: A unilateral declaration would be directed by the Head of State or Government at the international community as a whole. It is binding, just like a treaty.  A state cannot be absolved from its obligation so established through agreement with other treaty parties. Instead, a change would only be possible in analogy to the law of treaties, for instance under the highly restrictive doctrine of fundamental change of circumstances noted above.

Option 2:  A Specific Obligation Not to Join NATO

Permanent neutrality excludes membership in any defensive arrangement. Another option is to negotiate instead a more narraow restraint—one that would rule out NATO membership without rendering Ukraine a neutral state altogether. The commitment could be focused on NATO alone, or it could cover association with several nominated military alliances, East and West.

Exclusion by NATO: The first option would be that NATO determines that Ukraine shall not be a member, departing from the decision taken at the Bucharest Summit of 2008. This seems very unlikely, given NATO’s repeated confirmation that it will maintain in place its ‘Open Door’ policy. However, if Ukraine itself declares that it will not seek NATO membership, NATO could record its understanding of this commitment.

Assurances by NATO Members: Second, key NATO members could offer assurances that Ukraine will not obtain membership. This could occur, for instance in the shape of the US side letter to an angreement, provided Ukraine first declares itself that it will not seek membership.

Self-Limitation: Ukraine itself would rule out NATO membership. If so, the question arises how this commitment will be anchored. As with neutrality, its commitment not to join a specific alliance could be anchored in Ukrainian legislation or its constitution, in an international agreement, or in a legally binding, unilateral declaration. Most likely, it would be a combination of the above.

If NATO membership is to be ruled out in this way, the question is whether this would be a time-limited commitment, say, for 12 years, of whether it would be permanent.

Option 3: Non-Aligned Status

Another option might be to commit to non-aligned status and membership in the Non-aligned Movement. The members of the non-aligned movement have committed themselves to refrain from joining the major alliances. However, there is no formal constitutional instrument of the Movement and the relevant obligations are essentially political, also relating to the common pursuit of progressive policies in relation to a range of issues, including a new economic order, defeating racism, opposing unilateral sanctions, etc. Accordingly, non-alignment would most likely give expression to a national policy preference, rather than the legally binding obligation under discussion by the sides.

Option 4: The European Union

The Russian Federation may insist that the neutrality it seeks for Ukraine would need to include a commitment not to join the EU. At the same time, the European Parliament, and some EU governments, are pressing for an accelerated EU accession process for Ukraine. Ukraine itself has now applied for membership and has reportedly insisted in the latest round of talks as of end of March that neutrality must not exclude the EU perspective.

It should be noted that EU membership is not incompatible with a commitment to refrain from joining NATO or any military alliance. Indeed, even if Ukraine were to commit itself to permanent neutrality, membership is not excluded.

As the membership of Ireland in the EC/EU demonstrated, and since then the addition of other members following a policy of neutrality, it is possible to modify participation in the EU upon accession to take account of this fact, despite the increasingly strong role of the EU in terms of common foreign and security policy. (See the safeguard clause in Article 42 (7): ‘This shall not prejudice the specific character of the security and defence policy of certain members states.’)

EU membership does include a commitment to the territorial integrity of the member states, though. According to Article 42 (7) of the Treaty of the European Union, ‘if a Member State is the victim of armed aggression on its territory, the other Member States shall have towards it an obligation of aid and assistance by all means in their power, in accordance with Article 51 of the UN Charter.’

An eventual EU Accession Treaty for Ukraine could perhaps delay application of this provision. On the other hand, perhaps this provision might actually assist on the issue of security guarantees for Ukraine, as will be noted in the next Options paper.

If a restriction on Ukraine’s EU ambitions is to be contemplated for a limited period of time, it might be possible at least to clarify that Stabilization and Association, and perhaps other steps towards fulfilling membership criteria, might continue.

The present EU-Ukraine Association Agreement provides in Article 7 (2) that Ukraine and the EU are committed to their respective territorial integrity. However, there is no provision for mutual defence.

Despite the present pressure to act rapidly on Ukraine’s application for membership, it may be that the candidate process will only be put in train once the terms of a settlement are available.  If the EU grants candidate status, this would again not be expected to include a collective defense dimension. Hence, at least up to the point of actual membership, which is likely to lie a decade or so in the future, this is not actually an issue of neutrality. Rather, it seems to be a broader concern of cultural and economic orientation.

In conclusion, if this issue is pressed by the Russian Federation, Ukraine might confirm its view in a legally binding way that EU membership would not be realistic, and will accordingly not be sought and obtained, for a period of some years. Any commitment going beyond that option would imply a very severe restriction imposed upon the future of Ukraine and its right to determine that future in the manner of a fully sovereign state.


The narrowest concession Ukraine could make on this issue is to rule out NATO membership specifically, without accepting permanent neutrality. This could be backed up by side-assurances from prominent NATO states (the US) that there is no prospect of admitting Ukraine to NATO for a defined number of years, or permanently.

If neutrality is to be agreed, a number of issues would need to be clarified. First neutrality would operate both ways—it would not only exclude NATO membership, but also affiliation with any Eastern alliance (should there be a political change in Ukraine at some point).

Second, would it be permanent neutrality, and if so, how is such permanence going to be established. The anchoring of neutrality will likely be double-or triple sown, consisting of an undertaking in the peace settlement, perhaps a restatement of such an undertaking in a guarantee document if there are to be security assurances, and possibly reference to the issue in a Security Council Resolution. There could also be anchoring in domestic or constitutional law.

In case of neutrality, there also need to be a clear confirmation for Ukraine of its right and indeed its obligation as a neutral state to arrange for an effective defense. This includes its right to receive support in acquiring armaments for this purpose from states or organizations of its choosing.

Under this reading of (armed) neutrality, arms limitations should only apply to WMD and weapons of longer range, capable of reaching deep into the Russian Federation. Permanent neutrality requires significant and effective forces able to assure other states that Ukraine is able to defend its territorial integrity. Deeper limitations relating to conventional weaponry would need to be balanced by effective international security guarantees.

Any restriction relating to participation in collective security arrangements (as opposed to collective defence and alliances) would not be consistent in international practice. This issue does not, in any event, arise during the EU stabilization and association phase, and also the candidate process. Even eventual EU membership can be rendered consistent with full neutrality. Indeed, such membership could offer an avenue towards a ‘non-threatening’ security guarantee for Ukraine in due time.

Model Draft Article

Option 1

Ukraine declares that it will not seek nor obtain membership in NATO. This declaration shall be transmitted to NATO, which will be invited record its understanding of this commitment.  

Option 2

Ukraine shall be a permanently neutral state. Such neutrality shall be enshrined in the constitution of Ukraine, following a referendum on acceptance of this peace settlement. The permanently neutral status of Ukraine shall also be referenced in a Chapter VII Security Council Resolution endorsing this settlement.

Ukraine shall not permit the basing of foreign armed forces on its territory. This includes the holding of joint manoeuvres with other states or alliances on its territory, or visits of foreign forces beyond a period of 12 days. Exceptions may be made with the agreement of the Russian Federation. A limited presence of foreign advisors for training purposes shall be permitted, up to an overall number of 85.

Subject to the clauses on arms limitation (demilitarization) in this agreement, Ukraine shall be entitled to maintain the armed forces (land, sea and air forces) it deems necessary to ensure its effective defense. To this end, it is entitled to receive support and assistance in developing its defensive capacity from friendly states.

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