Trump-Proofing NATO: 2% Won’t Cut It

As Donald Trump remarked that he would ‘encourage [Russia] to do whatever the hell they want’ if NATO allies failed to ‘pay their bills’, NATO allies rushed to announce that 18 of its 31 members are set to spend 2% of GDP on defence this year. Despite the fact that Russia has been waging a war against a European neighbour for two years, hitherto only ten European allies have met this NATO-agreed defence spending target. Yet the idea that simply spending 2% will secure Europe is mistaken. To ‘Trump-proof’ the Alliance, Europeans should focus not on reaching a budget target, but instead on putting in place the right concepts and capabilities to deliver deterrence by denial with minimal US support. Once the ends are agreed, the means conversation should follow – and 2% may prove insufficient.

To begin with, it should be clear that spending 2% does not simply secure continued US commitment. Trump is known not only for his transactional view of the Alliance, but also for his scepticism towards it. Various experts expect Trump to abandon NATO no matter how much its members spend. If, under a second Trump administration, the US commitment to NATO indeed collapses, Europe will need to step into a void left by an ally that for 75 years has provided both the Alliance’s leadership and its strategic backbone. But even if the US does not withdraw, Moscow may expect otherwise, and use a second Trump presidency to test NATO cohesion. In recent weeks, Europeans have grown increasingly worried about potential provocations along NATO’s eastern flank. To prepare for a time when not only is the US security guarantee in the balance but also the deterrent effect of NATO is undermined, European capitals should get ready to deliver deterrence by denial with minimal US support – as a signal to Washington as well as Moscow.

Deterrence by Denial

Any sound strategy signalling European seriousness about defence in both intent and effort cannot be centred on a simple spending target. It should instead involve a more urgent endeavour that demonstrates to Russia that an aggression against a European NATO ally will be unfeasible or unlikely to succeed, regardless of who is in the White House. This can be achieved through deterrence by denial, in which conventional means inflict such damage on invading forces that an opponent will think twice before deciding to test NATO resilience. Put differently, a European denial strategy would show that no adversary can ‘do whatever the hell they want’ to NATO territory. Even if Europeans cannot simply take over the command and planning of large-scale combat operations overnight, they can ‘Europeanise NATO’ by investing in capabilities and manpower to fill critical roles currently shouldered by US forces. Beyond deterring Putin, this would make the US commitment less costly and more attractive, potentially preventing full abandonment. Coincidentally, this approach would also prepare Europe for a scenario in which not a lack of will but a lack of capacity prevents Washington from coming to its rescue.

To effectively deliver deterrence by denial, Europe needs the capabilities to secure key government and military functions across its territory, to strike and defend against adversary forces probing NATO borders, and to retake potentially lost territories. For sure, Russian forces’ initial performance in Ukraine cautions against overestimating Russian military power, especially in relation to NATO. But Russia has also demonstrated its ability to learn and adapt, and to employ broader state resources to achieve strategic advantage. And while the war has taken its toll on Russia’s land forces and the Black Sea Fleet, the Russian air force’s material losses are relatively modest, while the country’s Baltic, Pacific and Northern Fleets, strategic missile force, and cyber and space forces remain largely intact. Experts have meanwhile warned about Russia’s capacity to rebuild its forces over a relatively short timespan. Thus, while NATO allies should not overestimate Russian military power, they should also not underestimate it – and they must prepare a solid deterrence architecture accordingly.

Russia’s long-range strike capabilities, which include SSC-8 ground-launched cruise missiles, demand a robust network of strategic and tactical missile defence systems to deny Moscow the ability to hold key assets across Europe at risk. Yet as Moscow is steadily expanding its missile arsenal and learning from missile intercepts in Ukraine, a strategy based solely on missile defence has become reckless. More generally, the cost–exchange ratio favouring the offender renders effective deterrence increasingly contingent on left-of-launch capabilities aimed at taking out the ‘archers’. Outside Europe, US allies facing precision-strike contexts have realised this, and have begun investing in deep-strike capabilities as part of their denial strategies. Still, investing in defensive and offensive missile capabilities is not enough. Any forces operating in non-permissive environments require critical enablers, including tactical command and control (C2), airlift, electronic warfare (EW), suppression of enemy air defence (SEAD), ISR and target acquisition capabilities. Somewhat incomprehensibly, following a decade in which Crimea was annexed, Ukraine invaded, Trump elected and Asia prioritised, European allies cannot assume responsibility for most of these roles and functions.

Europe’s Capability Gap

Certainly, Europeans have gradually increased defence spending since the NATO Wales Summit in 2014, and even more so since Russia’s full-scale invasion of Ukraine in 2022. Yet today, even the most capable European NATO members, such as France and the UK, are unprepared to conduct large-scale combat alone against Russia. As a result of a decades-long focus on out-of-area operations, they lack sufficient heavy manoeuvre forces, naval combatants and missile defence capabilities. Critical enablers and long-range fires are few and far between.

At the strategic level, Europe’s missile defence architecture is built around the US-led European Phased Adaptive Approach (EPAA) that includes Aegis ships, land-based ballistic missile defence sites in Romania and Poland, and an AN/TPY-2 radar in Turkey. Apart from hosting US assets, Europeans do little to contribute. Moreover, EPAA is oriented towards Iran and is unequipped to counter Russian missiles. A Europeanisation and reorientation of the strategic missile shield would require European capabilities, as well as technical and geophysical refinements. At the tactical level, Europeans field various air and missile defence capabilities, but not all systems are sufficiently networked. Efforts have been made to expand and coordinate European capabilities, for instance through the European Sky Shield Initiative, a not uncontroversial German-led initiative. In January, a coalition of NATO members announced the procurement of up to 1,000 Patriot missiles to enhance production capacity, replenish stockpiles and secure further supplies to Ukraine. While these are important and necessary steps, European missile defence efforts have been criticised for being unstructured, fragmented, and generally too incremental.

When it comes to long-range strike capabilities, Europeans lack sufficient fires beyond the 300 km range, especially ground-launched systems. Recognition of this ‘missile gap’ is growing in European capitals, but no firm conclusions have been drawn, let alone a plan put in place to address it. Poland and the Netherlands seek to equip their navies with Tomahawk cruise missiles, while France and the UK are developing hypersonic systems. A number of allies that possess F-35 fighters, including Finland, Germany and the Netherlands, are procuring JASSM-ER missiles. These efforts are helpful, but scattered and certainly not enough – not least given that ships and aircraft would likely perform different roles in the early stages of a NATO contingency.

Finally, efforts to overcome Europe’s overreliance on the US for enabling capabilities are slow, despite consistent reporting on these shortcomings. One recent analysis of Europe’s air enablers (airlift, refuelling, tactical and operational C2, ISR, EW and SEAD systems) highlights that capabilities continue to fall short in virtually all these areas. This means that without US support, Europe’s F-35s cannot operate effectively. Such gaps stretch well beyond the air domain: at sea, on land and in space, US ISR capabilities far outmatch European ones, even when combined.

Beyond 2%

NATO allies have realised before that an effort to address European defence shortcomings goes beyond a simple spending target. The Defence Investment Pledge made in Wales in 2014 included equipment spending requirements and output measures. Today, the strategic conversation on how to ‘Trump-proof’ NATO should focus on the roles and responsibilities European allies need to fulfil to close the Alliance’s emerging deterrence and commitment gaps. What is almost certain is that 2% won’t cut it, at least initially. During the Cold War, defence spending routinely averaged above 3%, including in Europe. The level required over the next few years could be close to that: following a 30-year ‘holiday from history’, Europe cannot simply catch up on its homework overnight. Fielding and integrating the right systems while achieving mass requires significantly higher levels of spending, not least because of inflation.

Certainly, European allies should try to spend as efficiently as possible. Increasing defence budgets without a plan to effectively ramp up production capacity, coordinate procurement, or integrate systems will not boost Europe’s defence capability to a level where it can close the conventional deterrence gap. European Commissioner Thierry Breton’s remarks that ‘we need to spend more, but we [also] need to spend better’ are as valid as ever. Still, some inefficiencies are inevitable in a defence context that is not and will not be fully integrated. Besides, more money does help: long-term and robust financing plans can incentivise defence industries to scale up production. Moreover, officials have suggested that capability requirements identified at last year’s NATO summit would amount to 3% of GDP across Europe.

One way to avoid such a spending increase would be to focus on deterrence by punishment instead of denial. Trump’s comments have reinvigorated a critical debate about a European nuclear deterrent, which explores if and how British and French nuclear forces could compensate for a US withdrawal. But, while necessary, discussions about a European nuclear deterrent should not overshadow those about the conventional dimension of deterrence. While the former is relatively cheap, Europeans have in the past been uncomfortable relying solely on nuclear escalation to make up for an unfavourable conventional balance. They should be again today.

The Indivisibility of Security

Finally, assuming responsibility for deterrence by denial requires not only a demonstration of effort but also of intent. In the past, Eastern European neighbours turned to Washington not just for its superior capabilities, but also because they trusted the American guarantee above any other. If European capitals want Washington to understand that the security of all allies is indivisible, they should believe it themselves – and make this belief evident to allies and adversaries alike. The critical role here of Europe’s largest military powers, including Germany, France and the UK, cannot be overstated.

The task of delivering deterrence by denial with minimal US support is not a small one. Europe needs to field sufficient air and missile defence systems, acquire deep strike capabilities, close its strategic enabler gap, expand combat forces, improve readiness, and bolster overall Alliance resilience. Success also requires that Europe’s bigger military powers make their commitment to the east more credible. This is not an easy task. Rising budgets come in a context of accelerating demand for European military and financial aid to Ukraine amid wavering US support. Despite what some may suggest, prioritising one over the other is not an option, as the issues at stake are closely connected. A Russia victorious in Ukraine could easily feel emboldened to probe elsewhere along NATO’s eastern flank.

The effort ahead is daunting, without doubt. But Europe has little choice, and those who await the outcome of the November elections waste valuable time. Because the issue at stake is this: while European capitals may still not be able to fully imagine a US withdrawal, Moscow can. This means that if Trump wins, by 2025, the risk of spillover to NATO territory will be unprecedented in the post-Cold War period. And one thing is clear: in case of a Russia–NATO conflict, European defence spending will no longer be limited to 2% – with or without US support.

The views expressed in this Commentary are the author’s, and do not represent those of RUSI or any other institution.

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