The Trump administration is sending shock waves through the development community, diplomatic circles, and financial markets. In doing so, it might have achieved something that, until a short time ago, even the most fervent Europeans would have downplayed as highly unlikely: European leaders seem to have finally recognized the need to take charge of their own defense.
In response to the Trump administration, the European Commission has launched the ambitious ReArm Europe Plan/Readiness 2030, which was unveiled in March 2025 and aims to mobilize 800 billion euros (approximately $872 billion) to strengthen the continent’s defense capabilities. According to the Financial Times, European officials believe “[i]t would take an estimated five to 10 years” for European countries, through a planned increased in defense spending, “to raise European capabilities to a level where they could replace most U.S. competences,” excluding the nuclear deterrent. However, such an ambition risks being optimistic.
To start, European countries depend on the United States for the architecture for long-range detection, identification, geolocation of static targets and tracking of mobile as well as for real-time transmission of the targeting data, beyond line of sight, over adversary territory as well as the airborne electronic warfare needed to neutralize enemy sensors, support operations, and address enemy countermeasures. Moreover, they rely on critical American military platforms, such as anti-submarine warfare aircraft; refueling aircraft; high-altitude, long-endurance unmanned aerial vehicles; long-range, high-altitude air defense systems; and multiple rocket launch systems. Additionally, European countries depend, to different degrees, on the United States for many different types of precision munitions — such as air-to-air, anti-radiation, surface-to-air, and surface-to-surface missiles — and they have limited stocks of them. Replacing such an extensive reliance on American assets, stocks, and technology will require time and will be industrially and financially demanding. Compounding these problems, European countries will need to recruit high-quality military personnel to address readiness issues and the new threat scenario they are facing. They will also have to identify how to train a new generation of professionals and strategists to anticipate, identify, and address these new threats.
A European Architecture for Modern War
Having an architecture that can detect, positively identify, and accurately track and geolocate mobile and static targets at a long range and that can transmit data on adversary targets from sensors to shooters in real time is critical for modern military systems. Without accurate and up-to-date targeting data, the long-range, high-precision missiles on which Western militaries rely are completely useless. In fact, while Western support to Ukraine in the form of HIMARS and ATACMS has received most of the attention, its provision of accurate, real-time targeting data derived from multisensor data fusion is much more important. When the Trump administration interrupted such targeting data, Ukraine’s capacity to engage targets at long range was significantly curtailed.
It goes without saying that developing such architecture is extremely challenging. To start, detecting and identifying enemy targets requires environmental and operational data so that signal-processing and machine-learning algorithms will be able to effectively and efficiently distinguish signals from noise. Such environmental and operational data, however, must be collected beforehand, which is particularly important for electronic signals. Like the smartphone app Shazam needs a library of songs in order to successfully “identify” which song is being played, modern military sensors need a library of unique signals associated with enemy platforms and unique signals associated with idiosyncratic environmental returns (e.g., specific type of fauna). The creation of such a library is a prerequisite for increasing the probability of accurate identification and for lowering the probability of misses as well as of irrelevant “radar anomalies” and false alarms.
Moreover, the architecture for precision-strike complex requires merging input (data fusion) from multiple sensors (e.g., radar, electro-optical, acoustic sensors) and platforms (e.g., satellites, airborne and ground-based systems). The goal is to accurately detect, identify, track, and geolocate targets while avoiding the same target being marked multiple times by multiple platforms and preventing mismanagement from occurring among different deconflicting zones (e.g., a target being detected and identified but not engaged with because it was thought to be the responsibility of a different area or a target being engaged by multiple assets). In fact, Russia lacks such an architecture — as demonstrated by its inability to strike Western supplies of weapons to Ukraine en route to the front lines — and at least until a decade ago, available information suggested that China lagged behind the United States in its precision-strike complex as well.
Further complicating the situation is the fact that it is even more challenging to carry out all these tasks effectively and efficiently while operating against a capable enemy over contested or adversary territory, as this entails dealing with enemy countertactics (e.g., camouflage, decoys, faints) and countermeasures (e.g., electronic warfare systems that also threaten advanced systems and space assets) that aim to blind and deceive sensors, damage and destroy platforms, and disrupt communications.
Dodging the Tinkering Trap
When it comes to starting the production of new technologies that European countries have not produced for decades or that they have not produced at all, European countries will have to design and develop new technologies, which will inevitably encounter technical problems, which will in turn require fixes and solutions, which will in turn generate new problems and hence require new fixes and solutions until, through constant tinkering, a working equilibrium is found.
Addressing these never-ending problems can easily get out of hand, and the defense industry provides plenty of examples of defense programs, even extremely successful ones, that encountered never-ending technical problems, which led to cost overruns and inevitable delays.
It is quite possible that European countries will be able to procure, design, develop, and manufacture the systems that they need in an effective and efficient way. Nevertheless, it is important to keep in mind that technical hurdles are ubiquitous in complex systems, especially in industries driven by technological performance like defense — these systems are subject to countless incompatibilities and vulnerabilities and, as a result, have extremely small and tight margins for errors.
Such technical problems call for both depth and breadth and, even more importantly, for defense companies to “know more than they make.” This is the business of systems integration, in which many European defense companies excel worldwide. Yet, developing such platform-specific expertise requires hands-on experience and thus time, as it spans a multiplicity of technical and organizational realms — from the technical properties of unique materials to the tacit understanding of trade-offs in design and to the knowledge and understanding of suppliers’ capabilities. Further complicating matters, these systems will need to operate against enemy countermeasures and countersystems in varying environmental conditions (e.g., humidity, salinity, sand, lightning) and need to be designed with several considerations in mind, such as ease of use and ease of maintenance.
Breaking Production Bottlenecks
Ramping up the production of the weapon systems and munitions that European countries currently produce will also not be easy. As the pandemic and then the war in Ukraine have clearly shown, increasing production cannot be done in a short time. There are multiple examples from the commercial sector of bottlenecks and choke points that threaten global supply chains. These problems are even more significant in the defense industry, since it requires specific physical and intangible goods with no easy substitute. Building new production plants or converting existing ones (e.g., from the automotive sector) would require effort, resources, and time, as companies would need to train or retrain workers, administrative personnel, and managers; to adopt industry-specific procedures to comply with government regulations (e.g., regulations for handling explosives and hazardous materials, for restricting access to security clearance holders, for meeting ITAR requirements, etc.); ordering and setting up specialized equipment (which will inevitably have backlogs in delivery because they are complex machineries, and only very few companies can produce them); building specialized laboratories and testing facilities; identifying, contacting, and vetting suppliers that can, within a given time frame, produce and deliver components that meet very specific and stringent technical requirements; and, of course, dealing with inevitable supply-chain problems, such as those regarding raw materials and critical minerals.
Mobilizing Talent
European countries will also have to grapple with the problem of recruiting high-quality military personnel. The modern military requires personnel who possess a certain set of cognitive, emotional, and interpersonal skills. Such requirements stem from the lethality of the modern battlefield, which has reduced the margins for errors and mistakes as well as the window for time-sensitive tasks. The increasing availability of multiple sensors and the trend towards a transparent battlefield further reduce existing margins and increase the qualitative requirements for military personnel. Yet, European countries are facing a series of intertwined challenges that are going to frustrate their attempts to recruit high-quality military personnel.
To start, many European countries are experiencing a demographic decline and, in particular, are seeing a reduction in the number of college-age individuals, which reduces the pool of potential recruits. Further reducing such a pool, a significant portion of young adults do not meet the standards required for military service. Together, these two aspects intensify the competition between the military and private industries for the required types of individuals. Private industries generally offer higher salaries, better benefits, and a more stable lifestyle compared to those offered by the military. In this regard, it is telling that competition in the labor market also poses problems for countries such as the United States, where the military is highly regarded among the general population. The U.S. military regularly fails to meet its recruiting goals — preferring to recruit fewer people than it needs and rejecting many applicants who fail to meet specific criteria.
For Europe, this problem would be further exacerbated by a set of cultural and institutional factors. Compared to the U.S. military, European countries’ militaries do not enjoy as high a social status, and there is no comparable Reserve Officers’ Training Corps (ROTC) system. Moreover, even the idea of defending the nation has little support among younger generations, and specific welfare provisions that exist in some countries are arguably going to further complicate military recruitment.
European countries might consider reintroducing the draft, which most of them suspended or abrogated it in the 1990s and 2000s. Whereas some countries, most notably Sweden, reintroduced military conscription in the late-2010s, such an option would not come without costs — especially in large countries such as France, Germany, Italy, and Spain — due to social conflicts, multiethnic tensions, and ideological opposition to the military.
Strategists, Not Accountants
In light of the challenges ahead, European countries will have to ask themselves a critical question that they have, until now, avoided: What is the goal of rearming Europe? In the abstract, the answer seems obvious: It is for deterrence and defense, primarily against Russia. But in practice, what European countries want to achieve is less clear. For example, are they pursuing deterrence by denial or by punishment? If the former, does it include an offensive operational component, such as long-range interdiction or offensive counter-air? If the latter, which targets will European countries intend to strike: only military targets, or critical infrastructure as well?
Moreover, deterrence is effective if it is credible. The fact that European countries changed the name “ReArm Europe” because some considered it too aggressive is definitively not a good starting point. If some European countries have a problem with calling rearmament what it is, their commitment to European deterrence and defense can be easily called into question given that such commitment would entail striking inside adversary territory. For deterrence to fail, all that is needed is for the enemy to not perceive it as credible.
More generally, European countries will have to ask themselves whether they intend to only pursue deterrence or whether they intend to actively undermine the Russian threat, for example, by imposing costs and creating strategic dilemmas for Russia similar to how the United States employed cost-imposing and maritime strategies in the 1980s. At some point, European countries will have grapple with these questions, and they will have to explain their answers to their citizens — that is, if they want to take responsibility for their own security. If they do not want to make the hard decisions, someone else will do it for them.
It follows that an increase in defense spending cannot simply be an accounting commitment — going from spending less than 2 percent of gross domestic product (GDP) to more than 3 percent (GDP itself being a shifting number that is changing due to ongoing tariff-related turmoil). There must be a clear strategy behind it. To this end, European countries will have to go through a paradigm shift in which defense policy is not dictated by finance ministers. European countries will have to strengthen and, in some cases, even develop a culture and institutions that will enable them to design, elaborate, and execute their defense policies. This will in turn require European countries to relearn the art of strategy, literally. As some commentators have eloquently pointed out, Western countries, in general, and European countries, in particular, seem to be incapable of recognizing contexts and situations that are outside the realm of the norms and rules with which they feel comfortable and adapting to new realities in which norms and rules play a secondary role, if any role at all.
However, the problem goes much deeper than this. European countries will also need to think about how to train next-generation strategists and how to promote their careers given that they will be defined by different parameters compared to other professional profiles. To address defense and security problems, it is not enough to simply increase defense budgets: countries need qualified civilian personnel who understand, among other things, the type of military technologies needed; the inherent trade-offs in weapons design; the issues that plague research, development, testing, and engineering in the defense industry; the considerations and goals that inform defense acquisition; and the drivers of military innovation. To date, there are, however, very few universities across Europe that offer classes in defense planning and policy, analysis of military operations, military technology and operations, and related topics. Moreover, strategic thinking also includes a speculative element that is inherently creative. This aspect requires professional profiles that might be completely different from traditional career paths in large governmental organizations, and European countries will thus have to devise a way to identify, recruit, and retain the right profiles.
Conclusion
The ambition to rearm Europe and develop its autonomous defense capabilities is necessary and cannot be postponed any longer. However, European countries will face significant challenges and constraints. Reliance on American technology and military infrastructure has been deeply embedded in European defense strategies for decades, making any shift toward independence a complex, costly, and time-consuming endeavor. Along these same lines, recruiting and retaining highly skilled personnel will be increasingly difficult for European militaries, which are up against demographic decline, reduced societal support for military service, and intense competition from the private sector. Addressing this issue may require fundamental cultural shifts, enhanced incentives, or even reconsideration of military conscription policies. Finally, a critical but often overlooked aspect of European defense readiness is the need for strategic expertise. Defense planning and military technology are complex fields that require specialized knowledge, yet European academic and professional training programs in these areas remain inadequate. Without investing in the education and development of future defense strategists, even the best-equipped military forces will struggle to formulate and execute effective security policies. In summary, while geopolitical realities justify Europe’s pursuit of greater military self-sufficiency, achieving this objective will require more than just increased funding. It will necessitate a long-term commitment to technological innovation, industrial expansion, military recruitment, and strategic education. Without a comprehensive and pragmatic approach, the vision of an independent European defense force will remain an aspiration rather than a reality.
Andrea Gilli, PhD, is lecturer at the University of St Andrews, senior advisor at the Office of the Undersecretary of Defense in Italy, and expert mentor at NATO’s Defense Innovation Accelerator of the North Atlantic. Previously, he was a senior researcher at the NATO Defense College, a post-doctoral fellow at both Harvard and Stanford universities, a visiting scholar at both Columbia and Johns Hopkins universities, as well as an associate fellow at the European Union Institute for Security Studies.
Mauro Gilli, PhD, is a senior researcher in military technology and international security at the Centre for Security Studies of the Swiss Federal Institute of Technology in Zurich. Previously, he was a post-doctoral fellow at Dartmouth College.
Niccolò Petrelli, PhD, is assistant professor at the Department of Political Sciences, Roma Tre University where he teaches strategic studies. Previously he was Eisenhower Defense Fellow at the NATO Defense College, post-doctoral fellow at Stanford University’s Center for International Security and Cooperation, a visiting scholar at the International Institute for Counter-Terrorism in Herzliya, and military researcher at the Military Center for Strategic Studies.
Image: U.S. Army photo by Capt. Thomas McCarty, accessed via Wikimedia Commons.
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