As the diplomacy on the Russia-Ukraine War accelerates following President Donald Trump’s summit with Russia’s President Vladimir Putin in Alaska and Ukrainian President Volodymyr Zelenskyy’s consultations with Trump and European leaders in Washington, so too has talk of a European “reassurance force” for Ukraine. Those backing the proposed force – which, according to a senior European defense official, would comprise roughly 5,000 troops drawn from a handful of European countries – see it as the linchpin of Western “security guarantees” once a ceasefire or peace agreement is reached.
Together with other elements of Western support, such as military assistance and training, this force is meant to reassure Ukraine that the West will stand behind it if Russia reattacks after a ceasefire. In theory, such an assurance would give Kyiv greater confidence to sign a peace agreement with the Kremlin, something it has been wary of since Russia’s full-scale invasion in February 2022.
Yet with troop strength projected at only about 5,000 — most likely deployed to rear areas — it is difficult to see how the force could meaningfully deter renewed Russian missile or drone attacks, which have been targeting Ukrainian cities and critical infrastructure in addition to frontline positions. The deeper problem with the reassurance force, however, is not its modest size or the capabilities it will have, but its highly questionable viability. Those European governments that have committed personnel to the force have been clear that their troops will only deploy once a ceasefire is in place. By taking this position, they have effectively handed Moscow a veto — unless they are prepared to do one of two things: either (1) compel Russia into accepting a ceasefire on terms it has repeatedly rejected; or (2) reverse their position and deploy troops while the fighting is ongoing. Absent either scenario, the reassurance force risks remaining a mirage, another notional “security guarantee” that offers little more than a false sense of hope.
Alternatives to NATO’s Article 5
Discussions of a Western military presence in Ukraine gained traction in 2024 as it became increasingly clear that NATO would not extend an invitation to Kyiv in the near term. For Zelenskyy and his government, NATO’s collective defense commitment has always been the one and only credible security guarantee. But by the 75th anniversary NATO summit in Washington in July 2024, it was evident that the United States and Germany, along with Hungary and Slovakia, would oppose granting Ukraine an invitation in the near term.
Although Ukrainian officials at the time viewed any talk of a ceasefire without a credible pathway to NATO with great suspicion, European leaders quietly began exploring interim arrangements. Within NATO, this produced the “bridge to membership” concept, unveiled at the Washington summit in the form of a new support-and-training mission designed to make Ukraine’s forces fully interoperable with the Alliance. In parallel, the “Capability Coalitions” created under the Ukraine Defense Contact Group – the loose coalition of 50 countries under U.S. leadership that provided Ukraine with weapons and military equipment – sought to identify and coordinate the provision of deterrent capabilities for Ukraine’s future force.
Trump’s election in November 2024 accelerated European thinking about a reassurance force for two reasons. First, Trump had strongly opposed Ukraine’s NATO membership during the course of his presidential campaign, signaling that Article 5 was off the table for at least another four years. Second, Trump’s repeated promises to secure a “deal” persuaded some Europeans that Washington could broker a ceasefire in 2025. Those facts, combined with the hostility Trump and senior U.S. officials displayed toward Zelenskyy in their Oval Office meeting in February 2025, led French President Emmanuel Macron and U.K. Prime Minister Keir Starmer to quickly advance the idea of a reassurance force composed of a “coalition of the willing.”
On March 2, Starmer hosted the first “Coalition of the Willing” summit in London, followed by a virtual meeting a few weeks later. Macron hosted the next meeting in Paris on March 27 to discuss a blueprint for the force based on more rigorous military and logistical planning. This was in turn followed by numerous additional planning sessions, capped off by another joint summit held virtually on July 10. But despite the intensity of these planning efforts, only a handful of countries expressed readiness to contribute troops, with most preferring financial or logistical support. Major powers such as Germany, Italy, and Poland have been skeptical or outright opposed to troop deployments, reflecting broader public sentiment across much of Europe opposed to direct engagement with boots on the ground.
Meanwhile, European diplomacy in Washington has focused on securing U.S. backing — diplomatically and through a vaguely defined “backstop,” interpreted as enablers or mission support short of American boots on the ground. Trump has ruled out deploying U.S. ground forces but has endorsed the concept of a European reassurance force and is weighing whether to provide “air support,” which would reportedly consist of strategic enablers such as intelligence, surveillance and reconnaissance (ISR), command and control, and air defense systems to support European troops on the ground.
Discouraging Assurances
At first glance, these discussions suggest momentum toward a resolution favorable to Ukraine. Zelenskyy has endorsed the idea of a robust reassurance force and encouraged further planning. Yet Russian officials have consistently and vocally opposed any European troop presence inside Ukraine. Foreign Minister Sergey Lavrov bluntly declared: “It simply will not work… In the West, and above all in the United States, they perfectly understand that seriously discussing issues of security without the Russian Federation is a utopia. It is a road to nowhere.”
Some European leaders, such as Finland’s President Alexander Stubb, counter that “Putin doesn’t get to choose.” But by their own admission, European leaders have said that a ceasefire must precede deployment, and Putin holds the power to withhold that ceasefire. This raises the uncomfortable question of why European capitals invest so much effort in planning for a deployment whose fate hinges on Moscow’s acquiescence.
Ukraine’s history offers ample grounds for skepticism of Western-proposed security guarantees that depend on Moscow’s tacit support. The 1994 Budapest Memorandum is the most glaring example: Kyiv relinquished its Soviet-era nuclear arsenal in exchange for pledges from Russia, the U.K., and the United States to respect its territorial integrity and the inviolability of its borders. When tested, during Russia’s invasion of southern and eastern Ukraine in 2014 and again during its full-scale invasion of 2022, those pledges proved hollow. More recently, since early 2024, some 25 countries have signed “Bilateral Security Agreements” with Ukraine, many of which promise military aid in case of renewed aggression. Yet none commits troops.
For Ukrainians, credible security guarantees are the indispensable core of any peace settlement. Ceasefires between 2014 and 2022 were numerous but almost always short-lived. Russia’s repeated violations — despite prior assurances and international commitments — have left Ukrainians understandably distrustful. Even the Organization for Security and Cooperation in Europe’s (OSCE) Special Monitoring Mission that was physically present along the frontlines from 2014 to 2022 was not structured or designed to deter ceasefire violations. During the Istanbul talks after Russia’s 2022 invasion, Kyiv insisted on firm guarantees, while Moscow sought a consultative model that preserved its veto — a framework Ukrainians rightly equated with a replay of the Budapest Memorandum. It is hardly surprising then that Ukrainian Foreign Minister Andrii Sybiha would note that, in his recent talks with U.S. and European counterparts, he “reiterated Ukraine’s position that security guarantees must be concrete, legally binding, and effective.”
Reassurance to What End?
The crux of the problem with current proposals for a reassurance force is that European leaders appear to view a ceasefire as some sort of deus ex machina that will be imposed on the warring parties. But that is a myth. The reality is that Putin has not backed away from his maximalist aims of subjugating Ukraine. Moreover, neither Washington nor European capitals have mustered the leverage to compel him to accept the one thing he has consistently railed against: the idea of NATO countries sending troops to Ukraine. Doing so would require far greater pressure — seizing frozen Russian assets, significantly tightening sanctions on Russian banks and oil revenues, imposing tariffs, and ramping up military aid to Kyiv.
Without these measures, it is hard to see how Moscow would suddenly abandon its longstanding demands: Ukraine’s demilitarization and the severing of its defense ties with NATO countries. Rather than devoting endless meetings to planning a reassurance force, Western policymakers would do better to focus on enabling Ukrainian success on the battlefield — which could be funded with the roughly 300 billion Euros in frozen Russian assets — and strengthening sanctions on Russia’s war economy. These are the tools that could eventually create the conditions for a ceasefire. Without such leverage, a reassurance force will remain little more than a fantasy.
