President Donald Trump is offering security guarantees for Ukraine and the wider European region as part of a peace process, which prompts the question: what is the US military's role on the continent worth?
Removing American might from the European equation raises queries over how much dozens of countries can invest to match the level of military readiness on offer today. The cost for Europe's defence in the event of a US military withdrawal following a Ukraine peace deal would be $1 trillion, according to a think tank.
That estimated total cost above $1 trillion would stem from the boosting of defence spending back to Cold War levels in terms of individual nations' GDP. The IISS estimate covers both one-off procurement outlays of almost $400 billion as well as support and associated costs over a 25-year assumed lifespan.
The additional purchases would be triggered as a first step during a “window of vulnerability” in which a dramatic increase in defence spending would be needed just to stand still. This means building 600 tanks and 10 nuclear submarines and adding 400 fighter jets, the International Institute for Strategic Studies (IISS) said.
That would need to be done at speed to meet a resurgent Russian threat, with the likelihood that Moscow would have reconstituted its forces by 2027. Russia's economy is already on a war footing, so it has the ability to produce 2,700 attack drones a month, and has an army that is experienced in modern warfare.
Europe’s Nato states have promised to increase their defence budgets from 2 per cent to 3 per cent of GDP. The bill would suddenly go much higher if the US started to withdraw 128,000 service personnel and their kit to concentrate on the Indo-Pacific region.
As US Vice President JD Vance has said, Europe must “step up in a big way to provide for its own defence”. This will require the continent’s powers to “reduce dependencies on the US and, in extremis, to prepare for a Nato without any US role”, the IISS report stated.
Fighter jets
The most expensive single item would be the purchase of 400 tactical combat aircraft, and training the pilots to fly them. But having many more squadrons of F-35 stealth fighters, Eurofighters and F-16s would give Europe a significant edge over Russia’s depleted air force.
This new air armada would cost up to $64 billion but Europe would also need other aircraft currently supplied by the US, including 15 P-8 Poseidon submarine hunters ($4.8 billion) and 200 attack helicopters, such as the Apache ($12 billion).
It would at the very least need a further 50 Reaper combat drones ($3 billion), given the game-changing impact of drones in the Ukraine-Russia war.
All its aircraft would need missiles, from Meteor air-to-air weapons to Storm Shadow cruise missiles, with a further 7,000 required at a high end cost of $16 billion.
Tanks and missiles
With drones making armoured warfare a much trickier undertaking, the 600 extra main battle tanks ($18 billion) required, such as the US-made Abrams or German Leopard 2, would also need to be more resilient.
Infantry fighting vehicles, which have proven their worth in Ukraine by protecting troops and providing firepower, would be a priority. A further 2,400 of all types would be necessary, costing $25 billion.
Given the importance of artillery, far more will be required, with at least 100 guns ($2.2 billion) and many more short or medium-range missiles such at the US-supplied Atacms, which have proven effective in Ukraine.
A total of 400 Atacms would be needed, as well as 27 extra air-defence batteries, such as the Patriot ($35 billion), which have been vital in defending Ukraine’s civilians and infrastructure.
Essentially, on land the continent would need an additional three armoured divisions to cover the US absence.
Warships and subs
A war at sea will require significant European upgrades to combat Moscow’s powerful Northern Fleet in the North Sea and Baltic Sea.
An additional 10 nuclear submarines ($22 billion), such as the British-made Astute class, would be required, even though they take a decade to build, along with a destroyer force of 20 extra ships ($50 billion).
A further four aircraft carriers would be necessary at a cost of $13.6 billion.
These will all need more missiles, from cruise to air defence and torpedoes totalling $25 billion, according to the IISS estimate.
Arms budgets
Given that much of the above will take years to assemble, alongside willingness among European powers to finance it, the continent would face a “considerable window of vulnerability” without US support, the report said.
Therefore, it might not have “much time to prepare for a Russian threat to allied territory” and would face “a wide range of capability gaps”. Europe would face stark choices on how to fill them, especially with aircraft production at global aerospace factories already at high capacity.
In the short term this would be “very challenging”, but given a few more years it “would not be an impossible task”, the authors suggested.
