How can a ‘Europeanized NATO’ defend Europe with reduced American support?

The Trump administration’s May announcement that it would withdraw some U.S. assets from the NATO Force Model and no longer serve as the primary guarantor of conventional European security in a continental conflict with Russia has tangible consequences for European NATO members. This brief will examine what reduced U.S. conventional support would mean for Europe’s ability to defend NATO territory on the continent against Russian aggression. It focuses on conventional military capabilities rather than questions of deterrence or nuclear escalation.

Assessing the ramifications of European NATO members receiving less American involvement in a conventional escalation on the continent requires us to distinguish between different timelines. After all, it makes a difference whether Europe must defend itself with less or no U.S. support tomorrow (“fight tonight”), only in a few years (“2029”), or during the transition period between these two scenarios. Europe may be able to replace much of America’s conventional military capability by the end of the decade. The more difficult challenge will be replacing the U.S. role in integrating, commanding, and employing those forces.

European progress and challenges ahead of 2029

In the “2029” scenario,¹ Europe has been working intensively since 2022—and especially since Donald Trump’s return to office—to significantly improve its defense capabilities before two developments occur: first, the United States withdraws additional military assets and personnel from Europe; and second, Russia regains the capability to launch a military attack on European NATO allies, whether through full-scale conventional aggression or a more limited test of NATO’s resolve.

Europe is broadly on track to fully replace, in the coming years, the conventional capabilities that the United States will withdraw from Europe or would no longer be able to provide to NATO in the event of a military conflict. Across areas such as tanks, fighter jets, intelligence, surveillance, and reconnaissance (ISR), deep-strike capabilities, electronic warfare capabilities, or drones, most European countries are placing orders and ramping up production at full speed. Domestic political developments—such as electoral victories by right-wing populist, pro-Russia parties or a drastic decline in public support for increased defense spending amid welfare cuts—could slow down or halt this trend. If they do not, Europe’s challenge will be ensuring these investments translate into the forces and capabilities needed to mount an effective continental defense.

However, this progress offers only limited cause for optimism that Europe will be able to defend itself fully and successfully against Russian aggression in 2029 with significantly reduced or no U.S. support. Two significant gaps remain in Europe’s efforts to mount a successful defense: “mass” and a lack of interoperability among European armed forces.

A key component of “mass”—the concentration of combat power at the decisive place and time—is the availability of troops. Yet most European countries are reluctant to return to universal conscription. Instead, they hope that programs designed to make military and reserve service more attractive will enable them to replenish their armed forces’ ranks. However, trends in Europe’s larger countries raise considerable doubts as to whether this approach will ultimately prove successful.

Even more importantly, without the United States—or with much less U.S. involvement—European armed forces would only be partially capable of effectively coordinating operations. For the past 70 years, European armed forces have been structured around U.S. capabilities, both in terms of their operational effectiveness and ability to conduct operations. NATO’s integrated command structure is the alliance’s military “brain,” which enabled Europeans to be integrated into the U.S. command structure and the U.S. way of warfighting. Without the United States, Europeans will be “brainless” for the foreseeable future. However, there is currently little discussion about how Europe—or who within Europe—could assume this central integrating function.

Which European country can take on the unifying role currently played by the United States? In my view, this task can only be carried out by the United Kingdom or France. Both have extensive experience working with the U.S. armed forces and are thoroughly familiar with American structures and doctrines. Furthermore, they are the only European nuclear-weapon states. Whether the other European countries are willing to accept this role, and whether the U.K. and France have the necessary number of officers trained for this purpose, remains an open question.

A European way of war?

Without the interface with the U.S. armed forces, and thus without the U.S. approach to warfare, another question arises: Does Europe have its own way of conducting warfare? This question becomes even more urgent in the “fight tonight” scenario, or during the transition period before Europe can replace U.S. capabilities. In such a scenario, Europe would almost certainly have to defend its territory against Russian aggression with little or no American support. Moreover, many of the substitute capabilities that European countries have recently ordered would not yet be available in this scenario. So, should a conventional conflict with Russia break out in the near future, European armed forces would lack the critical strategic enablers, the manpower, the coordinating and directing role of the United States, and sufficient conventional military equipment of their own. Meanwhile, they would have to face a Russian military hardened by its war of aggression against Ukraine.

Under these conditions, it would be nearly impossible for European armed forces to implement the U.S. concept of European defense, which relies on striking quickly, hard, and deep into the Russian rear area.

If the U.S. concept of defense becomes infeasible, what alternatives would Europe have? In my view, two priorities would become essential in such a scenario. First, maintaining the political cohesion of the European coalition defending itself; and second, shifting the operational focus away from winning and toward not losing.

Maintaining political cohesion is crucial for three reasons. First, in a conventional conflict with European states, Russia will draw nuclear red lines quickly. These red lines could undermine support for active conventional defense among some states and societies within the coalition. Keeping all coalition members committed to the fight will thus become critical for the broader defense.

Second, and closely linked to the nuclear issue, European states are likely to disagree regarding whether and to what extent the defense of European NATO territory should involve strikes into Russia. Coalition management will therefore become a priority, but it will constrain defense efforts with regard to strategic and operational issues.

Third, a Russian attack will not necessarily be limited to conventional military means. The more hybrid the conflict’s nature, the more likely it is that European coalition partners will disagree over whether and how to respond militarily.

Operational limitations in a “fight tonight” scenario

In terms of operational strategy, a “fight tonight” scenario would see European states facing significant limitations across three dimensions.

1. Capabilities. European states, if left to their own devices, are not yet capable of maintaining freedom of action across all the domains required for a successful defense. They lack the necessary capabilities in the areas of electronic warfare, cyber warfare, space-based capabilities, and deep precision strike.
2. Geography. Europeans mostly lack the firepower and maneuver capabilities needed to operate deep within the adversary’s territory to identify and eliminate key command nodes or systems.
3. Readiness. A lack of ISR capabilities, including limited European early warning systems, would prevent Europeans from quickly understanding battlefield developments and reacting at the necessary speed. As a result, they would have to overextend their defensive lines, as they could not precisely know where the enemy is concentrating its attacks.

These constraints would fundamentally shape a European approach to warfare. Most significantly, they would render any defense strategy relying on speed obsolete under such conditions, because European states would lack the capabilities to implement it. Maneuver warfare, aimed at recapturing or conquering territory through movement, would be replaced by the concept of holding and defending territory in order to delay the enemy’s advance for as long as possible.

Given Europe’s limited personnel capacity, sustaining such a strategy over the long term would require the extensive deployment of drones and data-enabled drone swarms near the front lines. These systems could inflict losses on the enemy, minimize one’s own losses, and help hold territory for as long as possible while simultaneously exhausting the attacker. If Europeans want to avoid positional warfare, military operators and planners must develop a strategy for how to restore maneuver warfare under these constraints.

However, such a strategy must be supplemented by the limited ability to attack targets in the enemy’s geographically proximate rear area to disrupt its reinforcement capabilities. Given insufficient ISR capabilities, traditional means of reconnaissance (such as foot patrols, scouting, mounted reconnaissance with light non-mechanized transport, contact and patrol flights, or visual observation) would become necessary to enable the early detection and countering of troop movements in the immediate geographical area.

A strategy intended to delay an adversary’s advance would be not only personnel-intensive but also equipment-intensive. It would demand large quantities of equipment, ranging from vehicles to ammunition, to be deployed and subjected to enormous wear and tear. In a potential war of attrition, it is therefore absolutely essential to replenish stockpiles. Without the ability to consistently supply frontline troops with equipment and to replace or repair damaged equipment, European militaries will only be able to sustain such a war for a limited time. Having well-stocked warehouses means purchasing more off-the-shelf items and massively expanding ammunition production.

Conclusion

This brief has explored how European NATO armed forces could defend against a possible Russian aggression with little or no American support. It has considered two scenarios: the frequently discussed 2029 scenario and the possibility of a “fight tonight” scenario.

With regard to 2029, I argue that Europe might be able to fill many of the capability gaps created by the U.S. withdrawal from Europe. However, two major challenges remain: replacing the “plug-in” command structure that the United States has provided within NATO for the past 70 years (which will not be an easy undertaking) and solving the problem of persistent personnel shortages.

A “fight tonight” scenario—or a conflict occurring shortly before European NATO armed forces have replaced U.S. capabilities—would present entirely different challenges. It would force Europeans to completely rethink their theories of defense and warfare. This brief has sought to outline what such a European approach would look like, as briefly as possible.