Ceuta and Melilla: Defence Begins Before Article 5

A military assessment of security guarantees, deterrence and the southern flank

Every so often, the same question resurfaces: are Ceuta and Melilla protected by NATO?

The question is legitimate, but framing it solely around which treaty article would apply after a potential attack is insufficient. From a military perspective, the analysis should begin earlier: what combination of political will, military capabilities and international commitments makes such an attack unlikely?

Treaties are fundamental, but no treaty defends a position by itself. Defence rests on three elements that should be distinguished: the legal framework that permits action, the political will to act and the military capabilities capable of turning that will into an effective response.

In the case of Ceuta and Melilla, all three elements are present, although not with the same degree of clarity. This is precisely where one of the most relevant strategic questions lies.

What Washington says

Spain joined the Atlantic Alliance in 1982. Article 5 of the Washington Treaty establishes that an armed attack against one or more Allies in Europe or North America shall be considered an attack against them all.

It is one of the main existing guarantees of collective security. However, immediately afterwards comes Article 6, whose importance is fundamental to understanding the debate surrounding Ceuta and Melilla.

For the purposes of Article 5, Article 6 geographically defines the territories covered by the guarantee, including the territories of the Allies in Europe or North America, the territory of Turkey and certain islands located in the North Atlantic north of the Tropic of Cancer, as well as certain conditions concerning the forces, vessels and aircraft of Allied countries.

Ceuta and Melilla are not expressly mentioned.

This is where the well-known debate arises. A strictly geographical interpretation encounters an obvious difficulty when attempting to automatically include both cities within the territorial description of Article 6. When this issue was raised with then-NATO Secretary General Jens Stoltenberg before the 2022 Madrid Summit, he referred specifically to Article 6 and recalled that the application of Article 5 ultimately constitutes a political decision to be taken by consensus among the Allies in the North Atlantic Council.

Therefore, simply stating that Ceuta and Melilla are automatically covered by Article 5 provides a degree of certainty that the text of the Treaty itself does not offer. But claiming the opposite — that NATO would not defend Ceuta and Melilla — does not directly follow from the Treaty either.

Between these two positions lies a fundamental strategic element: uncertainty. And poorly managed uncertainty can affect the credibility of deterrence.

There is more to the Treaty than Article 5

Public attention tends to focus on Article 5, but there is another provision immediately before it that is also relevant.

Article 4 establishes that the Allies will consult whenever, in the opinion of any of them, the territorial integrity, political independence or security of any of the parties is threatened.

It is not an automatic defence clause. It is a mechanism for political and strategic consultation. Nevertheless, in a real crisis it can acquire considerable importance.

Contemporary conflicts do not necessarily begin with a formal declaration of war or a conventional military offensive. They can develop through economic pressure, disinformation, border incidents, sabotage, cyberattacks, the instrumentalisation of migration flows, calculated provocations or limited actions specifically designed to remain below the threshold that would trigger a large-scale military response.

A rational adversary may seek precisely to exploit these grey zones in order to obtain advantages without triggering an open war.

For this reason, the problem of Ceuta and Melilla should not be analysed solely through the hypothesis of a conventional invasion. One of the most strategically complex scenarios lies below that threshold: a succession of incidents whose authorship may be disputed or whose individual severity may be insufficient to justify escalation, but whose cumulative effect eventually alters the strategic situation.

In this context, the debate ceases to be exclusively legal. It becomes a question of deterrence.

Then there is Europe

There is also a second international security guarantee that often receives less attention: Spain's membership of the European Union.

Article 42.7 of the Treaty on European Union establishes that if a Member State is the victim of armed aggression on its territory, the other Member States must provide assistance and aid by all the means in their power, in accordance with Article 51 of the United Nations Charter.

The wording is relevant. Article 42.7 does not contain a territorial limitation equivalent to that established in Article 6 of the Washington Treaty. Ceuta and Melilla form part of Spanish territory and, therefore, the legal debate within the European framework has different characteristics from that existing within NATO.

This does not mean that there is a European army that would be automatically activated in the event of an attack. No such mechanism exists. The clause establishes an obligation of assistance and aid between states, while military capabilities remain fundamentally in the hands of the Member States themselves.

Furthermore, for countries belonging to both organisations, the European security architecture itself recognises NATO's importance as the principal framework for collective defence.

It is therefore necessary to distinguish between a political-legal obligation and an automatic military mechanism. Confusing the two can lead to mistaken conclusions.

The first line of defence is national

Above all these mechanisms lies a basic reality: Ceuta and Melilla are Spanish territory, and their defence is, first and foremost, Spain's responsibility.

The statement may seem obvious, but it has important strategic consequences. A military alliance works more effectively when a potential adversary knows that the state under attack has the capacity to resist from the very beginning.

If initial defence depended exclusively on different capitals holding consultations, interpreting a treaty or reaching an international consensus, part of the initiative would be left in the hands of the aggressor.

Alliances multiply national strength. They should not replace it.

In Ceuta and Melilla, this consideration takes on particular importance because of their geography. They are small territories, physically separated from mainland Spain and located in North Africa. In a serious contingency, the fundamental question would not simply be which forces are initially deployed, but the ability to sustain them, reinforce them and maintain their communications.

From a military perspective, a position is not measured solely by the garrison it contains. It is also measured by the ability to sustain it.

This requires viewing the Strait of Gibraltar as a single strategic space.

The Strait as a system

Gibraltar, Algeciras, Ceuta, the western Mediterranean, the Atlantic approaches and the Alboran Sea are distinct areas, but they form part of the same operational problem.

Spain possesses a strategic singularity within Europe: it controls one of the two shores of the main maritime gateway between the Atlantic and the Mediterranean and maintains sovereign territory on the North African coast.

This position creates vulnerabilities, but it also provides strategic depth and relevance for the Allies.

Major commercial and energy routes pass through the Strait. It is also a fundamental route for naval movements between the Atlantic and the Mediterranean.

For this reason, a serious crisis around Ceuta or Melilla would hardly remain isolated for long as an exclusively local problem. Geography itself would contribute to internationalising it.

The strategic question for Spain is not merely that Ceuta and Melilla are relevant to its own security. It is also important that their security forms part of the Allies' perception of the security of the southern flank.

The distinction is significant.

The southern flank exists

In recent years, European military attention has been significantly concentrated on the eastern flank. The war in Ukraine has demonstrated that high-intensity conventional warfare remains a reality in Europe, while countries along the Alliance's eastern border have strengthened their capabilities and NATO has adapted part of its planning.

Spain participates in this effort. Solidarity among Allies is one of the pillars of the Alliance.

But precisely for this reason, Spain also has grounds to insist that European security has a southern dimension.

The Sahel, the Maghreb, the western Mediterranean and the nearby Atlantic present risks different from those found in the Baltic. Terrorism, state instability, the instrumentalisation of migration pressure, competition between powers, the proliferation of unmanned systems, cyber threats, energy dependence and the growing presence of external actors form a strategic environment that cannot be analysed exclusively from a continental perspective.

Ceuta and Melilla are part of this southern flank.

Morocco

Discussing Ceuta and Melilla without discussing Morocco would hardly be realistic. But doing so requires precision.

Morocco is an important partner for Spain in areas such as security, counter-terrorism, trade, migration and regional stability. At the same time, Rabat maintains a position on Ceuta and Melilla that differs from Spain's.

Both realities can coexist. International relations are, in fact, full of situations in which cooperation and differences in interests exist simultaneously.

The role of foreign policy is precisely to prevent a disagreement from developing into a crisis and a crisis from ultimately becoming a conflict.

From a military perspective, Morocco should not be analysed exclusively as a threat or exclusively as a partner. It is a neighbouring state, with its own interests, growing capabilities and considerable importance for Spanish security.

Defence planning is not about predicting intentions. Intentions can change. Capabilities, by contrast, take years to develop.

Responsible planning must observe both variables without turning either into a political prophecy.

The value of ambiguity

At this point, an inevitable question arises: should the Washington Treaty be amended to explicitly include Ceuta and Melilla?

From a political perspective, it can be argued that an explicit reference would reduce uncertainty. However, from a strategic perspective, the issue is more complex.

Deterrence does not depend solely on legal clarity. It also depends on the perception a potential adversary has of the consequences of its actions.

Ambiguity can become problematic if it creates the perception that an attack could go unanswered. But legal ambiguity can also coexist with a high degree of political and military certainty about the consequences of an attack.

The decisive question is which perception prevails on the other side.

Spain's security therefore depends on several elements simultaneously: credible Armed Forces, a strong relationship with its Allies, participation in NATO planning and a coherent strategy for the southern flank.

Treaties matter. Capabilities matter too. And the political will to use them is another fundamental element.

Do not wait for Article 5

The best defence of Ceuta and Melilla would be one that never had to be put to the test.

To achieve this, two extremes should be avoided. The first would be to permanently dramatise the situation until the two cities become permanently besieged fortresses. Apart from being unhelpful, this could be strategically counterproductive.

The second would be to assume that their security is automatically guaranteed simply because Spain belongs to NATO and the European Union.

Deterrence is built before a crisis. It is built through presence, intelligence, surveillance, response capabilities, logistics, secure communications, air and maritime defence, civil resilience and coordination with Allies.

But above all, it is built by eliminating from the mind of a potential adversary one particularly dangerous idea: that there is an action limited enough to obtain a political advantage without provoking a proportionate response.

The public debate will continue to ask whether Ceuta and Melilla are covered by NATO. The rigorous answer will continue to be less straightforward than a simple yes or no.

Article 6 of the Washington Treaty raises a genuine geographical question regarding the application of Article 5. Article 4 provides a consultation mechanism in the event of threats to the territorial integrity or security of an Ally. Article 42.7 of the Treaty on European Union also establishes an obligation of aid and assistance if a Member State suffers armed aggression on its territory.

And beneath all these mechanisms lies a fundamental reality: Spain retains the right and responsibility to defend its own territory and must possess the capabilities necessary to do so.

The strategic objective should not be to reach the point at which it becomes necessary to determine how the Allies interpret Article 6. By then, deterrence would already have failed.

The serious work is done beforehand: ensuring that any actor considering action against Spanish territory knows that Spain has the capacity to respond from the outset; that it can sustain that response; that a crisis would be difficult to isolate from the wider strategic environment of the Strait; and that an act of aggression would trigger consultations and international commitments whose ultimate scope no adversary can completely control.

That is deterrence.

It is not about promising war. It is about making it credible that starting one would carry costs and consequences that would be difficult to control.

And, in the case of Ceuta and Melilla, that strategic certainty may prove more decisive than any isolated interpretation of a footnote in a treaty.