Should European countries provide Ukraine with genuine security guarantees?
The Big Ask | No. 08.2025
Last week in Brussels, Pete Hegseth, Secretary of Defence of the United States (US), outlined the new administration’s position on European security and the future of Ukraine. Namely, that the US can no longer be ‘primarily focused on the security of Europe’, that restoring Ukraine’s pre-2014 borders is an ‘unrealistic objective’, and that Europe ‘must provide the overwhelming share of future lethal and nonlethal aid to Ukraine’.
While Hegseth has partially retracted these statements, Donald Trump, President of the US, has maintained that North Atlantic Treaty Organisation (NATO) membership for Ukraine was ‘unlikely’ while also beginning unilateral negotiations with Vladimir Putin, President of Russia, over terms to end the Russian full-scale invasion of Ukraine.
With an aggressive and expansionist Russia to the east and an increasingly withdrawn America to the west, European nations find themselves in an unenviable position. However, the outcome of Russia’s war against Ukraine will be critical for ensuring European security as a whole. So, in this week’s Big Ask, we asked six experts: Should European countries provide Ukraine with genuine security guarantees?
Director, Geopolitics and Security Studies Centre
Europe must move from the sidelines and take an active role in shaping Ukraine’s future. Security guarantees are crucial, yet it’s unclear whether European countries are in a position to consider it. The ongoing debate over Europe’s inability to defend itself without the US only adds to the credibility problem – how can Europe offer Ukraine meaningful guarantees when it struggles with its own security?
But this can change. First, a coalition of willing European nations should seriously consider deploying troops to Ukraine – not as peacekeepers, since there is no peace to keep, but to protect critical infrastructure in western Ukraine or similar strategic areas. While this wouldn’t be a military game-changer, it would send a clear message to Russia that Europe is no pushover, catch Trump’s attention, and provide a much-needed morale boost to Ukrainians.
Second, Europe must ramp up defence spending. But not through fragmented national efforts, but by leveraging the European Union’s (EU) economic power. A defence-focused equivalent of the Pandemic Recovery Fund is needed. Germany, post-election, may no longer be a veto player, and in the meantime, the European Commission should redirect existing recovery funds toward defence. Matching tough rhetoric with concrete action is the only way forward.
Senior European Security Analyst, Polish Institute of International Affairs
It is vital to ensure security guarantees for Ukraine, not only from the Ukrainian perspective, but also for the security of Europe. Trump’s decision to start negotiations with Russia surprised America’s allies, but this does not yet determine the final shape of any deal and creates an opportunity for the Europeans. Their firm stance will determine the shape of the agreements on Ukraine and their implementation, as well as the future architecture of European security. Recent meetings in Paris show that European states – not only EU members but also the United Kingdom (UK) – are capable of presenting a united front and engaging in constructive dialogue.
It is too early to propose solutions along the lines of future security guarantees or a peacekeeping mission, as the talks in Saudi Arabia that were supposed to lead to an agreement on Ukraine have not yet produced any concrete results. However, European countries must take a more proactive stance to ensure decisions on European security are made independently from the great power relationship between the US and Russia. EU treaties provide opportunities for enhanced security cooperation between member and non-member states, and these should be utilised immediately. Europeans should invite Ukraine to join the Permanent Structured Cooperation (PESCO) framework, create a Rapid Deployment Capability with the UK, or any other viable solution, should be put on the table as a matter of urgency.
With a clear vision of the future, Europeans should have the knowledge and tools to move forward.
Associate Fellow, Council on Geostrategy
The answer is yes, but European nations will struggle to make them genuine, secure or guaranteed. Because what we learned from last week is a two-fold truth about the global order.
First, the US nuclear contribution to Article 5 deterrence – which Hegseth implicitly left on the table while signalling the drawdown of conventional security – will likely be used conditionally. With the Trump administration everything is now leverage, and if it does not get what it wants on a variety of issues, it is prepared to hollow out NATO at precisely the level of deterrence Europe lacks – intermediate nuclear weapons.
Second, the only powers that enjoy freedom of action in the world now are large, modern economies with capable armed forces and nuclear deterrence. That’s what Trump’s appeasement of Putin signals. So in order to provide any kind of security guarantee for Ukraine, European powers have to be united, militarily capable, and prepared to practise deterrence by punishment.
I favour the creation of a core alliance of European states willing to deter Russia from restarting its aggression with Ukraine (if a peace can be signed) through the use of conventional force. Those same states could act as a backbone for a wider diplomatic alliance – because it obviously cannot be NATO or the EU that does this, though the EU has played a remarkably strong hand in this crisis so far.
What it means for the UK, to return to the boringly prosaic, is that His Majesty’s (HM) Treasury needs to get its head around a very simple equation: losing a war to Putin is a bigger fiscal humiliation than re-setting your own borrowing rules. The facts have changed. Time to change your mind.
Senior Lecturer in International Politics, Aberystwyth University
Trump is backing away from US security cooperation with Europe at high speed and apparently would rather cut deals with the Kremlin than support Ukraine. Although a combination of domestic and international pressure on the White House might manage to pull this administration back from the brink of de facto withdrawal from NATO, European countries can no longer assume that the US is a reliable security partner, at least as long as Trump is in office. Any genuine security guarantees for Ukraine therefore must be provided by European countries.
A European commitment to the security of Ukraine would not be an altruistic move, but would be a necessary step to demonstrate serious resolve in the face of increasing Russian hostility towards the Euro-Atlantic. Putin’s Russia already regards itself as being at war with the so-called ‘West’. Moscow fears the spread of values such as democracy and human rights will threaten the regime’s hold on power, while it seeks to gain advantages over European states by covert operations such as sabotage, assassination and manipulating elections to help its chosen political parties achieve power. Helping the Ukrainians to secure their country against Russian aggression is the best way to increase the security of Europe as a whole.
Co-founder and Director of Research, Council on Geostrategy
It depends on many different factors. If the outcome of Trump’s diplomatic efforts with Putin leads to some kind of ceasefire or peace agreement, which the Ukrainians then accept, European countries should follow through and deploy troops to whatever is left of Ukraine.
But there should be no misunderstanding as to what this would entail. The deployment must not be a lightly armed peacekeeping force, but a heavily-armed deterrence force, ultimately backed by British (and ideally French) nuclear weapons. To deploy only a peacekeeping force would be dangerous; the Russians would not fear it – it may even invite aggression, leading potentially to a serious crisis.
Any deterrent force must be large enough and sufficiently ‘fortified’ into Ukraine that, should Russia invade in the future, it would be hard for Britain and other European countries to disengage. It would need heavy emphasis on naval and air assets, as well as multipliers for the Ukrainian Armed Forces with which it would need to intersect. The deployment would need to be supported by powerful rhetoric from the British (and French) leaders as to the consequences should the Kremlin re-initiate war. Successful deterrence depends on a visible chain of escalatory mechanisms from initiating first contact to the release of nuclear weapons.
To do this, European governments, Britain’s included, need to begin rearming by elevating investment in their armed forces. The situation is acute. The UK should lead the way by moving to spend at least 2.5% of Gross Domestic Product (GDP) on defence within the next year, with a full plan to move to 3% or even 3.5% by 2030. If this delays the publication of the Strategic Defence Review by another few months, so be it.
Minister of Defence of Ukraine (2019-2020) and Chairman, Centre For Defence Strategies
European security guarantees for Ukraine are probably the most viable option, assuming the fact that the new US Government will not provide such guarantees. European countries – specifically several EU member states, the EU as a multilateral institution and the UK – have indicated their readiness to participate, and there are good signals coming from Norway as well.
Currently, there are capabilities’ gaps which cannot be closed without the US, but perhaps they can be arranged with the new American administration on acceptable commercial terms. The biggest question is if the guarantees will include military units participation or just materiel. If units are engaged, their mission types and rules of engagement will be a key question to resolve.
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