Europe confronts the cost of securing Ukraine without American backing

European leaders gathered in London over the weekend to sketch out security guarantees for Ukraine, a direct response to Donald Trump's declaration that the United States will not underwrite Kyiv's safety. The meeting followed a White House encounter in which Trump and Vice President JD Vance publicly berated Volodymyr Zelenskyy for resisting an unconditional peace plan with Russia. The message from Washington was unambiguous: Europe must now carry the burden.

The scale of the American security umbrella

Since the end of the Second World War, the United States has been the anchor of European security. As of July 2024, roughly 65,000 active-duty US soldiers were permanently stationed across the continent, supported by six pre-positioned weapons stockpiles holding tanks and armoured vehicles, eight air squadrons, four navy destroyers and an estimated 100 nuclear bombs. An additional 10,000 troops rotate through Poland, the keystone of NATO's eastern flank. The financial muscle behind this posture is a defence budget of $860 billion in 2024, more than double the combined spending of every other NATO member. That budget has also funded the bulk of direct military aid to Ukraine: approximately $65 billion since the 2022 invasion, with total US allocations reaching $183 billion when humanitarian and financial assistance are included.

By comparison, the European Union has committed $141 billion in total aid to Ukraine, of which $51 billion is military. The disparity reflects not just wealth but the structural reality that European militaries have long relied on American enablers, strategic airlift, satellite intelligence, air defence, nuclear deterrence, that no single European state possesses at scale.

What Europe actually fields

On paper, NATO's European members are formidable. They collectively maintain two million active-duty soldiers, with Turkey (481,000) and Poland (216,000) fielding the largest forces. France and Germany follow at 205,000 and 186,000 respectively; the United Kingdom, which has offered peacekeepers, has 138,000. The alliance's own eastern flank force numbers about 40,000 spread across seven countries. In equipment terms, European NATO members operate roughly 7,000 aircraft, 6,800 tanks, 2,170 military ships and six aircraft carriers, according to the Global Firepower index.

But aggregate numbers mask dependency. In a major conflict, NATO planning has always assumed the United States would surge hundreds of thousands of additional troops, backed by advanced command-and-control, precision strike and logistics infrastructure that Europe lacks. The economic think tank Bruegel estimates that replacing US capabilities would require Europe to create 50 new brigades, each several thousand strong, a force generation task that would take years and hundreds of billions of euros.

The spending response so far

The shock of Russia's 2022 invasion jolted European capitals into action. NATO allies across Europe and Canada increased defence spending by an unprecedented 18 percent in the aftermath. Today, 22 of 30 European NATO members meet the 2 percent of GDP benchmark agreed in 2014 after Russia's annexation of Crimea. The United Kingdom announced last week it will raise spending to 2.5 percent of GDP by 2027, adding roughly $16 billion annually to a current budget of $68 billion. Starmer called it the biggest sustained increase since the Cold War.

Germany, long criticised for underinvestment, created a special fund of more than $100 billion to modernise the Bundeswehr after the invasion. Its annual defence budget hit 2 percent of GDP for the first time since reunification in 2024. Friedrich Merz, the CDU leader and presumptive next chancellor, has said the military will need at least €84 billion a year going forward, a figure that would require sustained political consensus in a coalition-prone system.

Trump's demand for five percent

Trump has dismissed the 2 percent target as insufficient, calling for European allies to spend at least 5 percent of GDP on defence. At a NATO meeting on February 12, Defence Secretary Pete Hegseth put it bluntly: "Stark strategic realities prevent the United States of America from being primarily focused on the security of Europe. European allies must lead from the front." NATO Secretary General Mark Rutte, speaking at the Munich Security Conference on February 15, conceded the point: "We have not paid enough over the last 40 years, particularly since the Berlin Wall came down. The US is rightly asking for a rebalancing of that. It's totally logical."

The gap between 2 percent and 5 percent is enormous. For Germany, 5 percent of 2024 GDP would imply roughly €200 billion annually, more than double Merz's €84 billion figure and nearly three times the current budget. For the UK, it would mean roughly £130 billion against a current £68 billion. No European government has committed to that level, and the political feasibility is questionable in economies facing stagnant growth, ageing populations and competing demands for health, pensions and green transition spending.

Russia's posture and the peacekeeper question

Russia fields at least 1.32 million active-duty soldiers, with hundreds of thousands currently engaged in Ukraine. Its equipment inventory includes 4,292 aircraft, 5,750 tanks, 449 ships and one aircraft carrier, smaller than NATO's combined European strength but concentrated in a single command structure and backed by the world's largest nuclear arsenal. Moscow has redeployed most of the 12,000 troops once stationed in Kaliningrad, its exclave between Poland and Lithuania, to the Ukrainian front. It maintains overseas bases across former Soviet states, the largest being the 201st base in Dushanbe, Tajikistan, with an estimated 7,000 personnel.

Russia's Foreign Ministry spokeswoman Maria Zakharova reiterated on February 18 that NATO expansion remains a core grievance: "Otherwise, this problem will continue to poison the atmosphere on the European continent." The Trump administration has said NATO membership for Ukraine is not "realistic." That leaves security guarantees, potentially backed by European peacekeepers, as the alternative. Macron and Starmer have both signalled willingness to deploy troops if a peace deal is reached, but the legal mandate, rules of engagement and command structure for such a force remain entirely undefined.

The capability gaps no budget line fixes quickly

Money is the easiest part of the problem. Even if European governments agreed tomorrow to spend 5 percent of GDP, the defence industrial base cannot absorb it at speed. Munitions production, while expanding, remains far below the throughput needed for high-intensity warfare. Critical enablers, strategic airlift (Europe relies heavily on the US C-17 fleet), airborne early warning, satellite reconnaissance, electronic warfare, long-range strike, are either absent or exist in small numbers. Nuclear deterrence remains exclusively French and British, with no shared European command. Integrating national forces into a coherent expeditionary capability requires not just procurement but doctrinal alignment, interoperable communications and a political willingness to accept casualties that has not been tested since the Balkan wars.

Kaja Kallas, the EU's foreign policy chief, put it plainly at the European Defence Agency conference on January 22: "Europeans need to wake up. The continent's failure to invest in military capabilities sends a dangerous signal to the aggressor. Weakness invites them in." The warning is directed as much at European capitals as at Moscow.

A European pillar or a European vacuum?

The London summit was a political signal, not a military solution. European leaders have accepted the premise that they must do more; they have not yet agreed on what "more" looks like in operational terms, who commands it, or how it is sustained without the American enablers that have underpinned every NATO operation since 1949. The numbers are stark: two million European soldiers versus 1.32 million Russian ones sounds favourable until one subtracts the forces tied to national commitments, the readiness shortfalls, the missing enablers and the nuclear asymmetry. The 50 brigades Bruegel identifies are notional; raising, equipping and sustaining them would require a defence industrial mobilisation Europe has not attempted in a generation.

There is also the question of political cohesion. A European security guarantee for Ukraine would require consensus among 27 EU members and 32 NATO allies, including Turkey, Hungary and Slovakia, whose governments have taken markedly different lines on Russia. The peacekeeper proposal floated by Macron and Starmer presupposes a peace deal to keep. If Trump negotiates a ceasefire that freezes Russian territorial gains, European troops could find themselves policing a line Moscow has no intention of honouring, without Article 5 coverage and without US air cover. That is not a security guarantee; it is a tripwire.

The deeper problem is that European strategic autonomy has been a slogan for three decades and a budget line for barely three years. The special funds, the 2 percent pledges, the joint procurement initiatives, all are real, but all are incremental. Trump's demand for 5 percent of GDP is almost certainly a negotiating position, but it exposes the truth: the gap between European rhetoric and European capability is measured in the very assets the United States provides and Europe does not. Until that gap closes, any European security guarantee for Ukraine rests on the hope that Russia believes the bluff. History suggests that is a dangerous wager.