Russia’s war of aggression against Ukraine has changed the EU’s calculus about the costs and benefits of admitting new states to the union. European leaders long dismissed Ukraine’s membership as a bridge too far, but opinions have shifted dramatically since the start of the war. Many EU officials and citizens saw Russia’s invasion as their so-called 9/11 moment: a game-changing event that posed a catastrophic risk to their values and way of life. Securing Ukraine’s place in Europe is now a top priority. Even enlargement skeptics, notably France, are now in favor.
EU leaders will decide in December whether to open accession talks with Ukraine. All signs point to the affirmative, although all twenty-seven member states reaching consensus is not a foregone conclusion. The accession process will take years and will transform both Ukraine and the union. Kyiv will have to undertake a long list of reforms to align its domestic law with that of the EU and to prove its merit as a democratic market economy. EU member states, meanwhile, are grappling with the myriad challenges that the addition of a large, relatively poor agricultural powerhouse will pose for the delicate balance of budgetary and decisionmaking powers in the union.
The EU can find solutions to these questions, as it has during previous enlargement rounds. But Ukraine’s accession poses a unique conundrum to which Europe has so far paid little attention: never in its history has the EU moved to admit a country that was in the midst of a major interstate war and lacked NATO’s security guarantees. Under Article 42.7 of the EU treaty, the union purports to offer member states a mutual defense guarantee akin to the one enjoyed by NATO allies. But the union cannot defend its external borders without NATO. That dilemma has long been a theoretical one, but Ukraine’s march toward membership could make it real.
The EU and member-state leaders must chart out a credible and sustainable path to ensuring Kyiv’s ability to defend itself, both during the yearslong accession process and once it eventually becomes a member. This should be done in partnership with the United States. Washington’s singular role in underwriting European security cannot be matched, especially as it is both the biggest contributor to and the facilitator of dozens of other nations’ military aid to Ukraine—even if U.S. staying power appears less certain as the 2024 presidential election approaches. The EU also must consider how Ukraine’s accession would radically reshape the bloc’s future security obligations. The union has taken steps to become a more coherent security actor, but Europeans still have a long way to go if they are to rise to the worthy task articulated by German Foreign Minister Annalena Baerbock: to ensure a zone of peace and prosperity “from Lisbon to Luhansk.”
Questionable Assumptions
European officials argue that the EU’s best security guarantee is membership. For Ukraine, the comprehensive, long-term reforms required in the accession process will indeed bolster its resilience against Russian coercion. By the time it joins the EU, Ukraine will have spent years strengthening its judiciary and independent media, fighting corruption, reforming its security establishment, and building sound public institutions. Ukraine will be more integrated into European energy networks and supply chains. And the EU has some efforts underway to support Ukraine’s cyber and digital resilience. But the EU and its member states must think beyond merely ensuring Ukraine’s resilience and instead imagine a world in which they might be on the hook to defend a new external border from Russian aggression.
The EU and its member states are sidestepping this difficult conversation, arguing that defending Ukraine in the future might not be the impossible task it now appears. Three scenarios underpin this optimism. First, many hope that Ukraine will join NATO before the EU, as the Central and Eastern European countries did in 2004. That scenario would entrust NATO, rather than the EU, with the obligation to defend Ukraine. Alternatively, many Europeans assume that an attack on the EU would prompt the United States to intervene because so many of its member states are also in NATO, even if the territory under attack were not part of the alliance. Others, meanwhile, are counting on Ukraine signing a durable peace agreement with Russia by the time it is ready to join the EU.
But these scenarios are far from assured. At present, NATO members are not willing to bring Ukraine into the alliance until the war is over. The allies—the United States in particular—do not want to take on an obligation to enter into direct conflict with a nuclear-armed Russia. This is neither surprising nor likely to change anytime soon, absent dramatic political shifts in Russia. With Ukrainian troops locked in a costly battle of attrition against dug-in Russian forces, total liberation of Ukraine’s territory is, at best, a long way down the road. And the prospects for a peace agreement with Russian President Vladimir Putin, who has shown no inclination to end his aggression against Ukraine, appear just as remote.
Some point to Cyprus joining the EU in 2004 as an example of the union admitting a new member with no NATO guarantee amid territorial conflict involving a third party, in this case Türkiye. Notwithstanding the fact that tensions between Cyprus and Türkiye are a persistent headache for EU policymakers, the case also differs in crucial ways from that of Ukraine. Cyprus had been violence-free for three decades by the time it joined the EU. And Türkiye’s NATO membership provides avenues for communication and crisis management that do not exist with Russia.
The EU must recognize that, in all likelihood, Ukraine will qualify for membership while still under acute Russian threat and not yet under NATO’s aegis. In its present state, the union is far from able to secure its interests in Ukraine and, eventually, to defend an expanded set of borders against Russian aggression.
Inching Toward Defense
The war in Ukraine has sparked a shift in the EU’s thinking about its role as a security actor. Though it was originally set up after World War II as a peace project, the EU has responded to repeated geopolitical convulsions by inching toward something that looks more like a defense union. Russia’s invasion of Ukraine has somewhat accelerated that transformation. But what appears like a revolution in Brussels remains much too slow when measured against the challenges at hand.
To be sure, the EU’s recent initiatives are useful. For instance, the union coordinates and facilitates some of the military aid that its member states provide Ukraine. It has marshaled €5.6 billion (about $5.9 billion) in common budgetary support to compensate member states for transferring equipment and munitions from their stockpiles to Ukraine, the first time in its history that the EU is supplying lethal aid to a third country. High Representative for Foreign Affairs and Security Policy Josep Borrell has suggested earmarking a €20 billion (about $21.2 billion) package to expand this military support for Ukraine over the next four years.
The EU also seeks to bolster Ukraine’s security by reinvigorating the union’s defense industrial base and building a sustainable pipeline of military aid. The war has revealed serious shortcomings in Europe’s defense industrial production capacity. Depleted ammunition and equipment stocks paired with long production lead times—down to a lack of specialized suppliers, skilled workers, facilities, and raw materials—betray a decades-long failure to plan for high-intensity conflict. In response, the European Commission has launched several new initiatives to facilitate common procurement, refill European stocks, and strengthen European defense firms over the long term.
Crucially, these defense industrial initiatives are viable only if the EU can galvanize and anchor member-state support in long-term programs. Predictability matters not just to Ukrainian defense planners but also to European firms that harbor doubts about the durability of European spending increases and are reluctant to invest in capability development without long-term contracts in place. Currently, most of the EU’s programs are set to end in 2025, and member states are a long way from delivering on their ammunition targets. As European and Ukrainian defense firms express interest in developing joint ventures, the EU risks missing out by not doing all it can to financially incentivize and support this defense industrial integration. Encouraging these links with the Ukrainian market makes sense from not just a military perspective but also a business perspective.
European Commission President Ursula von der Leyen is working on a long-term European defense industry strategy to make the EU’s initiatives more coherent and sustainable. A successful strategy would require the commission to mediate intra-EU disagreements over capability planning, arms export policies, and the right balance between procuring defense equipment abroad and producing it at home in Europe. So far, there are few signals that member states are willing to tackle those challenges, and defense planning is likely to remain fragmented.
Conceptual Blinders
Sustaining military aid and defense industrial support for Ukraine will be difficult enough. But the EU’s focus on these efforts has overshadowed debate over its security guarantee to union member states. EU and member-state officials acknowledge that Ukraine will benefit from the union’s mutual defense clause in Article 42.7 once it officially becomes a member. Article 42.7 commits EU countries to aid fellow member states that fall victim to an armed attack “by all the means in their power.” It has been invoked only once, by France, following the November 2015 terror attacks in Paris. In practice, however, the article has mostly remained a paper tiger. For years, the EU’s focus was on low-intensity crisis management operations only.
The EU has neither the experience nor the military planning and command and control assets of NATO. Most European governments have no interest in discussing how Article 42.7 would apply in a classic territorial defense scenario, much less in investing in the ability to back up this commitment militarily. EU member states have done little planning or resourcing to make the article credible, in large part because the EU has always outsourced questions of continental defense and deterrence to NATO—and, thus, the United States. Washington, for its part, has discouraged European discussions of “strategic autonomy,” fearing that a real European military capability outside of NATO’s command structure would weaken the alliance and undercut U.S. power.
When it comes to territorial defense, Russia’s aggression has, paradoxically, lowered the EU’s ambitions. Finland and Sweden were once among the most vocal champions of giving Article 42.7 greater heft, but their decisions to pursue NATO membership after Russia’s invasion signaled how hollow the EU’s guarantees really are. Only four EU member states will remain outside of the Atlantic alliance once Sweden joins. The EU’s most recent security and defense strategy—published only weeks after Russia’s invasion of Ukraine—does little to operationalize Article 42.7. Recent attempts to pressure test the mutual assistance clause through EU-led exercises have focused only on space- and cyber-related contingencies.
Although Article 42.7 only applies to full member states, the EU’s inability to safeguard its core interests without NATO will not only be an issue when Ukraine is ready for membership; it would also pose a problem during the yearslong accession process. Some EU officials have suggested that Ukraine could gradually integrate into union structures as it passes key benchmarks on the way to full membership. Kyiv could, for example, acquire the right to participate in specific aspects of EU decisionmaking or benefit from EU budget instruments and programs in stages. Although others are skeptical of phasing in membership, such an approach would build important incentives into the long and onerous accession process, ensuring that Kyiv stays the course.
This possibility presents its own security challenges, however. The EU’s core interests would increasingly be at stake under a gradual integration framework as Ukraine gained greater access to the single market, common funds, and decisionmaking structures. The union could make a strong case, for example, that Ukraine’s economic reconstruction, future joint production sites between Ukrainian and European defense firms, and the country’s Black Sea export routes are all of vital EU interest and must be secured with European military capabilities.
But for now, even the notion of relocating the EU’s limited military training mission, currently hosted on EU soil, to Ukrainian territory during wartime appears to be a nonstarter. Instead, EU officials are considering including Ukraine in some of the union’s defense cooperation frameworks—such as the Permanent Structured Cooperation (PESCO), which aims to help EU countries jointly develop and field new capabilities—and plan to integrate Ukrainian troops into some of the union’s crisis management operations. These steps may be useful during Ukraine’s accession process but come nowhere close to meeting Ukraine’s significant security needs or protecting the EU’s interests.
Meanwhile, outside of Brussels, the European Political Community (EPC) has been proposed as one solution to the security demands of candidate countries on the path of gradual EU integration. Set up in October 2022 as an intergovernmental forum for political and strategic discussions, the EPC includes all European countries other than Russia and Belarus. But the EPC’s most recent gathering in Spain was widely considered a disappointment. The project’s ambitions remain modest, and discussions center on the nonmilitary aspects of European security, including energy, cyber, and infrastructure security.
Bridging the Gap
As long as Europe is not prepared to defend its own borders and interests and NATO stands pat in its policy not to admit Ukraine, the EU accession process must be paired with a credible interim security arrangement that enables Kyiv to defend itself. U.S. involvement is critical. No other nation is capable of marshaling dozens of Ukraine’s partners to resource and deliver the weapons and training Kyiv needs in a timely fashion and at the required scale.
The joint declaration signed in July by G7 leaders and the EU is a good start. The signatories pledged to “formalize. . . [their] enduring support” through “specific, bilateral, long-term security commitments” aimed at ensuring that Ukraine is equipped with a future military force capable of defense and deterrence. Intelligence, defense industrial, and cyber cooperation are part of the plan. The United States and other countries are now negotiating with Kyiv on their specific future obligations.
A U.S.-backed interim security arrangement for Ukraine is within reach. Crucially, it is possible no matter how long the war lasts. Even in a stalemate, such an arrangement can help Ukraine achieve strategic victory as a prosperous, flourishing democracy increasingly integrated into Europe and capable of repelling any future Russian attack.
Europeans should not lull themselves into acquiescence, however. They will have to commit significant resources over multiyear time frames, bilaterally and through the EU, to ensure the success of an interim arrangement. And even a robust interim framework will fall short of a guarantee to intervene militarily if Ukraine is attacked. It does not absolve the EU of that responsibility once Ukraine is a full member state.
The Road Ahead
After years of abstract debates and theoretical disagreements over Europe’s so-called autonomous defense ambitions, the current discussion on the security and defense responsibilities that come with enlargement should focus minds. The EU’s member states need to get serious about their military capabilities.
The union has put itself in a tough spot, having agreed to admit Ukraine without a U.S. security guarantee. To make matters worse, the political momentum around enlargement risks fading as the war drags on. As the domestic costs of enlargement become clearer to EU member states, even stalwart defenders of Ukrainian security interests may start to wobble in their support. Poland’s recent spat with Ukraine over grain exports is a case in point. It heralds bigger challenges ahead as the enlargement process sharpens economic and potentially political competition between Warsaw and Kyiv.
Some European officials worry that talking about defending Ukraine down the line risks derailing an already fraught enlargement process. They want to cross that bridge when they get to it and prioritize sending messages of support to Ukraine now. But ignoring the challenge and hoping for a miracle—either that the United States will swoop in at the last minute with a defense guarantee or that the war will end before accession—would be irresponsible. Doing so risks gravely undermining the credibility of the EU’s promises to Ukraine. It also has the unfortunate effect of leaving the field open for leaders like Hungary’s Prime Minister, Viktor Orbán, who recently was the first to explicitly address the security challenges of enlargement when he said that Ukraine’s accession should be put on hold until the war is over.
Instead, European policymakers can make a compelling case that anchoring Ukraine in institutional Europe will be key to ending Russia’s aggression and denying Putin his main objective of breaking Kyiv’s ties to the West. It will also set Ukraine on a path toward economic revitalization. They can even argue that Ukraine’s EU membership would give Europe significant new defense and deterrence capabilities, insofar as Ukraine’s Armed Forces are now among the most experienced in high-intensity land warfare. European militaries are already overhauling their approach to battlefield medicine in response to lessons learned from the war in Ukraine. And European defense firms realize that they stand to gain from cooperating with Ukrainian firms in order to capture battlefield innovations and satisfy Kyiv’s—and Europe’s—long-term weapons needs.
If they want to move ahead on admitting Ukraine to the union, the EU and its member states must not only commit to their new defense industrial initiatives but also spell out the significance of Article 42.7—and, ultimately, develop a strategy and the capabilities to make it more credible. In a widely read recent report on EU reforms required for enlargement, a group of French and German experts recommended that member states clarify that “for security and stability reasons, countries with lasting military conflicts cannot join the EU.” This hard line will become the default if countries do not address the security implications of admitting Ukraine in the years to come. Those with an interest in Ukraine’s European future should work to instead equip Europe to take on that responsibility.
Since the EU currently has neither the capabilities nor the political mandate to handle high-intensity military confrontations, Europeans are likely to instead rely on multinational ad hoc or regional military coalitions of the willing—for instance, the UK-founded rapid reaction Joint Expeditionary Force (JEF)—to address future security emergencies. The governments involved in these formats need to think about how they might integrate Ukraine into their efforts. In a promising move, the JEF members have already offered Ukraine observer status for all exercises during 2024 and 2025. But the EU also needs to work on clarifying how these forums would relate to its own on-paper guarantees.
For its part, Washington will have a critical role to play in the unfolding EU debate about enlargement. It should clarify, ideally on a strong bipartisan basis, the nature of its long-term commitment to training and equipping Ukraine’s Armed Forces. At the same time, it must communicate its redlines when it comes to NATO enlargement. Misplaced European hopes for a change of heart in Washington will only stunt the EU’s maturation as a security actor. Moreover, recent turmoil in the U.S. Congress over aid to Ukraine is a timely reminder that U.S. policy toward European security could shift substantially after the 2024 presidential election. Europe would be well advised to continue building the so-called European pillar of transatlantic aid to Ukraine in case U.S. policy dramatically changes.
Ukraine, meanwhile, will continue to press for NATO membership, which it sees as its only path to true security. But President Volodymyr Zelensky was right to call on the EU in October to prepare to defend itself autonomously, especially with future U.S. policy increasingly uncertain. Kyiv should not underestimate what the EU can do for it from a security standpoint. It must keep reforming to ensure that it can reap all of the benefits of the accession process. For example, it should embrace an overhaul of corporate governance in its defense sector in order to spur deeper cooperation with Western firms that hesitate to jump into a notoriously murky Ukrainian industry. Kyiv also must preserve and strengthen its democratic ideals amid its legitimate imposition of martial law restrictions during wartime. At the same time, Ukraine’s leaders must avoid setting unrealistic expectations about the timetable for EU membership, lest Ukrainians’ enthusiastic support curdle into resentment.
Hard security, not just economics and democratic values, will be at the forefront of the EU’s next round of enlargement. European countries, Ukraine, and the United States have a lot of work to do to scope out an ambitious strategy for Ukraine’s long-term security and European integration. Taking in Ukraine could advance the EU’s transformation from regulatory juggernaut to geopolitical actor—a net benefit for both Europe and the United States. If mishandled, however, the move could kill any hope of Europe’s ability to provide security in its own neighborhood. Getting this right is necessary not only to show Putin that he is fighting a losing war but also to show the Ukrainian people a light at the end of the tunnel.
