European Strategic Defence Autonomy and NATO Cohesion: Assessing Complementarity in a Multipolar Security Order

Order Transformation

1. Introduction

In 1991, the Cold War’s bipolar order collapsed, prompting scholars to argue that liberal democracy had become the endpoint of ideological evolution. The 1992 book End of History by Fukuyama summarizes this, by proclaiming that liberal democracy had triumphed as the ultimate form of governance, suggesting that ideological evolution had reached an endpoint after the Cold War and https://ipr.blogs.ie.edu/ Autonomy and Complementarity in a of stability within the western world has been shaken by environment, renewed geopolitical tensions and the shift of Europe’s defence vulnerabilities. This paper examines within its member states can reinforce NATO cohesion. framework under the Lisbon Treaty, the Strategic Compass, the upcoming decades. Assessing the political and industrial It argues that coordinated capability development, burden strategic defence autonomy into a credible pillar that NATO-EU Relations, Great Power Competition, Security the collapse of the Soviet Union. Placed in this context, and echoing the optimism of Kant’s 1795 essay, Perpetual Peace. It was the beginning of a new era in the international arena. Kant argued that due to states' sharing of norms, institutional constraints, and mutual economic interdependence, they tend not to go to war with each other. Yet this apparently stable trajectory soon revealed its fragility. Liberal optimism has been deeply shaken in a way that surprised the western scholars such as Fukuyama. Paradoxically, the rise of populism and democratic decline at the same time, the resurgence of authoritarian powers such as China and Russia, challenged the hopes of a unipolar, liberal world order. The international system gradually evolved towards multipolarity, where multiple models of governance power centres coexist and contest influence. In 2021, Fukuyama gave a lecture, “The American State in a Multipolar World”, at Cornell University, and his reflections marked a clear departure from the early 1990s liberal triumphalism. The global balance of power had fragmented into multiple, often illiberal poles. Against this shifting landscape, Europe’s ability to act coherently as a security actor has become both a strategic necessity and an unresolved political question. 1.1 The E.U. and NATO The European Union and NATO have embodied the momentum of the post-Cold War order, extending through Eastern Europe. The EU’s main tool was the creation of stability through economic interdependence, while NATO ensured deterrence under a renewed transatlantic framework. But security order and balance have been challenged by recent events. The resurgence of Russian aggressions in Ukraine, geopolitical rising tension around South China Sea, and an increasingly unstable Middle East have revealed the limits of liberal integration and the fragility of global stability. Demonstrating how regional flashpoints progressively eroded the assumptions of the post-Cold War liberal order. NATO’s cohesion weakened amid diverging threat perceptions and shifting U.S. focus, while the EU faced internal disunity. The E.U naivety around defence was abruptly faced with the reality of a war confronting Russia on the old continent at the borders of member states. This multipolar with fast evolving conflict led to a strategic shock and revived a long-standing debate; should Europe continue to rely structurally on the United States, or develop the capacity to act autonomously while remaining embedded in the transatlantic alliance? NATO members continue to guarantee European defence, but echoes from Brussels are getting louder about a European Union ambition for strategic autonomy for defence, industry and deeper defence integration. The concept remains contested in theory and practice, but it does lie at the heart of Europe’s response to renewed geopolitical instability for the upcoming decades. Against this backdrop, this paper asks under what conditions European strategic defence autonomy can reinforce, rather than undermine, NATO cohesion. This raises the question of whether Europe can transform its institutional mechanisms into a coherent defence posture that strengthens NATO cohesion while asserting its own capacity to act in an increasingly multipolar world. The central argument advanced here is that European defence autonomy contributes to NATO cohesion only when it reduces fragmentation, enhances burden sharing, and embeds all new EU capabilities within fully interoperable transatlantic structures. In this context, the paper explicitly asks under what conditions European strategic defence autonomy can reinforce, rather than undermine NATO cohesion, arguing that complementarity and integration are the determining factors. The thesis of this paper is that strategic autonomy in terms of defence capabilities and European integration strengthen NATO when it becomes a coordinated European pillar rather than an alternative to the Alliance, within an emerging multipolar security order. 1.2 Structure of the Research The paper first examines the current architecture of EU defence within the NATO structure. It will then analyse the theoretical and institutional dimensions of defence autonomy and their implications for NATO unity. Finally, it outlines policy measures to align European defense integration with transatlantic cohesion in the multipolar security environment. A credible European pillar requires standing multinational force packages, consolidated procurement mechanisms, and shared command arrangements that plug seamlessly into NATO. As a whole, it will argue that, designed around complementarity, European strategic defence autonomy can act as a catalyst for NATO cohesion. It can strengthen collective deterrence, balance transatlantic responsibilities, and ensure Europe’s strategic relevance as the United States prioritises the Indo-Pacific region.

2. Background: Europe in a Multipolar Security

Order 2.1 From Liberal Triumph to Multipolarity This section examines how Europe’s pursuit of strategic autonomy, as shaped by the EU’s Strategic Compass, may transform fragmented defence governance into an Alliance-relevant power structure. The E.U current defence framework is crafted under the Lisbon Treaty signed in 2007. This treaty reframed the Common Security and Defence Policy (CSDP) and the Permanent Structured Cooperation (PESCO). CSDP acts as a political mandate, and PESCO on the other side acts as a cooperative capability engine. Since 2007, additional competences have been introduced, including the European Defence Fund (EDF), which provides a financial backbone for the EU’s defence initiatives. Those multiple developments and evolutions have laid the foundation for a more cohesive defence posture. On the other hand, the question of integration remains uneven and politically contested. Can the EU move from an institutional ambition to a strategic reality? Following the Russian aggression on Ukraine, the EU issued the “Strategic Compass”. It establishes a clear framework for the bloc’s security and defence in the coming years and seeks to position the EU as a stronger and more capable security provider. It sets common objectives for the member states and establishes actions within a time frame to improve the EU's ability to act decisively in crises and defend its interests. This Strategic Compass structures the current governance framework of the EU-27 into four pillars: Act, Secure, Invest, and Partnership, and closes the pre-existing gap between legal competences of the union and their actual usable force. Under the first pillar, “Act”, the EU commits to creating an EU Rapid Deployment Capacity of up to 5,000 troops, supported by strategic enablers such as airlift, medical support, secure communications, and regular live exercises under EU command. This is directly relevant for NATO if fully implemented, as it would provide a standing pool of better-trained, interoperable European forces and enablers that remain under national control but can be employed in EU or Alliance frameworks according to the single-set-of-forces principle. 2.2 The EU-NATO Order and Its Fractures The Strategic Compass offers a roadmap for unity of purpose and capability planning that NATO can employ. Three years after the release of the Strategic Compass, the four pillars around which it was constructed have been translated into concrete change and actions through the launch of multiple EU missions. First of all the Military Assistance Mission for Ukraine and the EU Rapid Deployment Capacity (RDC) are set to become operational by 2026, enabling the deployment of up to 5,000 troops. On an Institutional stance for defence and, the third EU-NATO Joint Declaration was released in

2023. It has emphasized cooperation and

complementarity. Although more symbolic than substantive, it shows an alignment in the political direction of both ends and a common objective that does not clash. Ultimately, what remains to be done after the treaties and declarations from the EU/NATO member states is political, and its strength will depend on the states’ cohesion in using collective power decisively. If the EU-27 continues to deliver results rather than declarations, autonomy will cease to be a rhetorical aspiration and become a functional instrument of European deterrence, to a rather than fragmentation in the transatlantic order. The Compass is not about the emancipation of NATO; it is about transforming Europe into a credible pillar within it, a pillar capable of shaping security outcomes, not merely reacting to them or serving as a parallel political showcase.

3. Analysis

3.1 Lisbon Treaty Framework: Sovereignty, Legal Limits, and Industrial Fragmentation The following question concerns the structural constraints and vulnerabilities from a political, operational, and industrial perspective that impede complementarity between the EU states. Will national sovereignty reflexes and industrial fragmentation continue to dilute collective power behind the 27 separate flags? Politically, the EU represents something akin to a geopolitical exception. It is a union of countries historically marked by recurrent conflict and which constituted the principal battlegrounds of both World Wars. However, effective governance in the EU comes at a high cost: the most precious resource a state possesses, sovereignty. Sovereignty refers to the supreme and ultimate authority within a territory, held by the entity that has the highest power to govern without external control. The EU already exercises a degree of influence over national sovereignty, as supranational legislation can supersede national legislation. To move beyond rhetoric and achieve genuine defence integration, member states must accept a trade-off that necessarily limits aspects of national autonomy. Legally, the European Union’s primary law limits integration in the field of defence procurement and production. It protects national autonomy in matters of essential security, which are connected with the production of or trade in arms, munitions, and war material”. This means that EU law allows member states to pursue their own industrial policy interests regarding armaments when it comes to defence contracts and procurement. Countries tend to lean towards protectionist measures to shield domestic industry from international competition. Industrially, markets for armaments are subject to high confidentiality requirements and service guarantees. In most cases, armaments are not standardised mass products. Production volumes are small and can be further limited by export restrictions. As the 2022 defence investment gaps analysis for EU leaders noted, the EU’s defence industrial base is characterised by “a number of national players operating in small markets, producing therefore small volumes”. As the primary clients of armaments companies, nation-states define demand for their armed forces within their production lines. This marks a significant barrier for the increased integration of EU countries and prevents economies of scale. Strategically, there is a dilemma revolving around giving up sovereignty within the Union since its creation, tangling European objectives with national concerns. For example, the discussion around an independent European nuclear deterrence led by France reflects growing concerns among member states as they are starting to have concerns about the long-lasting presence of the USA. Both organisations, NATO and EU, conduct defence planning, yet there is no legislative power to force member states to create equipment programmes that are coordinated or engage in pooled procurement. The European market is not well served, as countries continue to buy arms mostly independently, leaving collaborative Research & Development and joint procurement low. Franco-German projects like the Future Combat Air System (FCAS) and the Main Ground Combat System (MGCS) were meant to be next-generation platforms showcasing deeper cooperation, but internal disagreements caused repeated delays, and it is uncertain whether either project will be completed. Europe finds itself with duplication of over a dozen tank, fighter, or ship types in service, missing economies of scale, and straining interoperability. The lack of unity leads to outcomes such as the importation of non-EU weaponry, further undermining the EU’s defence-industrial base. Ultimately, the European Union framework that binds its member states plays a crucial role in strengthening coordination, but this will occur only if there is a pragmatic, and not domestic interest-based, approach focused on filling critical capability gaps. 3.2 U.S. Strategic Reorientation and the Pressure for a European Pillar The U.S. strategic reorientation to the South China Sea acts as a catalyst for deeper European defence integration. The United States has long constituted the European Union’s member states’ closest ally, yet shifts in U.S. strategic priorities have raised concern among European states. While the United States remains central to the security strategy of many European states, the growing US emphasis on China has reduced the strategic attention on Europe in American defence planning. Despite the current shift, there is a dependence on US imports for advanced technologies, high-end military capabilities, and soldiers. This reorientation weighs heavily on the continued reliance by Europe. The enduring asymmetry exposes the structural imbalance within the transatlantic relationship, shedding light on how Europe’s security architecture remains deeply contingent on U.S. military power and deterrence. In 2022 there was a current total to more than 100,000 service members of the US army across Europe. This also includes extending a Carrier Strike Group, deploying additional fighter squadrons and lift, tanker aircraft, and deploying an Amphibious Readiness Group and a Marine Expeditionary Force. The white House shares about 22 percent of the relatively NATO Common Funded budget out of the 32 countries, representing a majority in spending. Over time, the relationship E.U.-U.S. was conceived as a security arrangement that solidified into a defining structural feature of the Alliance. European states progressively aligned their security and defence postures with Washington’s leadership, while the United States became accustomed to the strategic leverage and political influence derived from its hegemonic role within NATO. From the presidency of Franklin D. Roosevelt to Donald Trump's second term, US policymakers have often supported efforts to strengthen European unity and encouraged allies to pool resources to improve collective resilience, first to counter the Soviet Union and now Russia. A more united and integrated Europe might also be less reliant on the United States to defend Western interests along the eastern flank. By doing so, the US also loses its long-lasting leverage and leaves Europe to pursue interests that risk not aligning with Washington. In January 2025, reports indicated that Trump planned to cut U.S. troop presence in Europe. He also placed emphasis on burden-sharing, asking European countries to make financial contributions for defence since, in his view, the U.S. should not bear all the cost of the deterrent presence. At the same time, analysts observed that the US under Trump planned increased military involvement in the Indo-Pacific region through deployments around the Philippines, deeper cooperation with Southeast Asian partners, and the establishment of pre-positioned equipment depots. In a speech at the 2025 Shangri-La Dialogue, Pete Hegseth (U.S. SecDef) said: “We are [...] re-orienting toward deterring aggression by Communist China.” This pivotal stance sheds light on a disposition of U.S. resources eastwards. This dynamic presses Europe to act fast, beyond a political stance. There is a change in the long-lasting alliance and in the burden-sharing that the US carried for Europe. Strategic autonomy for defence and integration do not represent a choice, but a rational survival necessity triggered by U.S. rebalancing.

4. Policy Pathways and Burden-Sharing

4.1 Making the Lisbon Toolkit Work In the early 2000s, the EU tried to create a joint confederation that would have encompassed all the nation-states under the same constitution. It was rejected by France and the Netherlands in referendums in 2005. To maintain momentum on integration, the Lisbon Treaty was signed in 2007. It gave the EU a legal personality and a renewed Common Security and Defence Policy (CSDP). Secondly, it leads to consolidation, turning security and defence into an EU competence rather than loose intergovernmental add-ons. The Lisbon Treaty consolidated the functions of the High Representative Vice President, making it easier for the EU to speak and plan more coherently on security and defence, acting as a recognisable single entity. More importantly, the Treaty has introduced the EU’s own mutual defence clause, which can function as a backstop or complement to NATO’s Article 5, especially in scenarios of partial or delayed U.S. engagement. This juridically anchors the idea of Europeans taking collective responsibility for their own defence. Articles 42 (6) and 46 TEU provide the treaty basis for PESCO and deeper defence cooperation among willing states, enabling capability development and interoperability in a way that can plug directly into NATO force planning rather than duplicate it. The issue lies in political willingness, not in the legal framework on which the EU has already built its defence foundations. This indicates that there is no need to rebuild from the ground up, but rather an urgency to act through incremental adjustments capable of producing substantive shifts in the status quo. For example, by framing CSDP into a highly integrated entity and as compatible with existing alliances, and by explicitly recognising NATO as the primary framework for collective defence. Lisbon locks EU defence into a complementarity logic rather than a rival bloc. 4.2 Recalibrating Burden Sharing and NATO Spending Commitments A pivot toward a more capable European Union would enhance NATO cohesion through a more balanced approach to burden-sharing. Burden-sharing is defined as the allocation of costs and responsibilities among allies in providing collective goods such as deterrence and defence emerges as a central mechanism for closing the fragmentation gap. In 2016, the Warsaw Joint Declaration crafted a strong base for initiatives between NATO and E.U. on hybrid and military threats and coordinated defence planning, strengthening the institutional link between the two pillars of European security. During the NATO Hague meeting, allies agreed to a 5% minimum spending divided into two essential categories. “At least 3.5% of GDP annually by 2035 to resource core defence requirements and meet NATO Capability Targets, with annual national plans outlining a credible path to this goal. Up to 1.5% of GDP annually will support critical infrastructure, cyber defence, civil preparedness and resilience, innovation, and the defence industrial base.” This spending plan will change the European average, which is expected as of 2025 to reach 2.1%. By more than doubling this level, the Union would inevitably reshape the burden-sharing dynamic, enabling a more deterrent Europe through the burden-sharing of the NATO allies. The plan is to be reviewed in 2029. 4.3 Creating joint EU-NATO Planning Mechanisms In order to reach this objective by 2029 and maximise the change, there is a need to restructure the incentives of defence and security within the Union. Multiple national actors operating within limited domestic markets result in low production volumes and hinder the ability to create the necessary lead capacities. A strategically autonomous Europe—aligned with, yet not dependent on, the United States, can sustain NATO’s transatlantic coherence while enabling a redistribution of burdens in an increasingly multipolar system. Burden-sharing comes into play through, first of all, a shared willingness and political measures. This arises through dynamic changes within the EU-NATO recalibration toward capability specialisation. There is a need for operational coherence by aligning EU defence initiatives (EDF, PESCO, EPF) to produce interoperable and deployable forces under a unified strategic framework. This can only be achieved by the industrial consolidation of the EU, overcoming fragmented national markets by pooling resources, joint procurement, and scaling production for efficiency. Creating a strong directional sense will lead to the EU Strategic Compass flourishing, yet there is a need to take into account the NATO defence planning process (NDPP) to avoid duplication and strengthen interoperability. 4.4 Industrial and Capability Reforms for EU-NATO Complementarity As of now, the EU possesses two main funding tools. The first one is the European Defence Fund (EDF), secondly the European Peace Facility (EPF). The Union must restructure its financial as well as legal incentives to push for collaboration within the European union states instead of a fragmentised union defence. EDF and EPF funding should prioritise multinational projects, shared logistics, and interoperable capability development, while expanding common cost coverage would reinforce collective defence efforts. At the same time, the establishment of a Joint EU-NATO Capability Registry, together with clear mobility and readiness benchmarks, would institutionalise burden-sharing and ensure that Europe can act autonomously while remaining fully interoperable within NATO’s framework. The change needs to come from what has led Europe to flourish as a joint entity in the past. Starting as the joint economic project under the European Coal and Steel Community, Europe’s integration was built on the principle that pooling sovereignty in strategic sectors could prevent conflict and generate collective strength. The EU needs to look to its roots to be redone in order to unite its defence capabilities. From fragmented national interests toward coordinated development and shared strategic planning. Just as economic interdependence around steel and coal led to a union that has secured peace by interdependence, it must today renew and secure stability, transforming the Union’s fragmented defence landscape into a cohesive framework capable of acting decisively, thereby sustaining prosperity and reinforcing NATO cohesion in a credible manner.

5. Conclusion

The trajectory that once defined the post-Cold War order has shifted, exposing Europe to a far more contested multipolar environment. The erosion of liberal optimism, combined with renewed instability and the United States’ strategic reorientation toward the Indo-Pacific, has revealed the persistent structural fragilities of Europe’s defence posture. Throughout this paper, it has been shown that European strategic defence autonomy on an operational or industrial stance becomes a strength for NATO only when framed through complementarity. The present frameworks built through the Lisbon Treaty, CSDP, PESCO, the EDF, and the Strategic Compass have already laid the groundwork for what Europe needs to become. In order to lead change and create actual impact there is still a hold back due to political hesitation, fragmented planning, and an industrial base divided into small markets with limited production capacity. Moving past this requires a turn toward coordinated capability development, a clearer and more balanced approach to burden-sharing and procurement practices that stop reproducing the repeated scheme of fragmentation. Only once done, the union can consolidate itself as a coherent defence actor. A stronger European pillar, reinforcing deterrence and threat from the east, strengthening NATO cohesion, and safeguards Europe’s strategic weight at a moment when the United States’ attention is increasingly directed towards south china sea. The future of transatlantic security depends on Europe turning this entire framework from a political ambition into something operational, usable, and decisive.