Why an ‘Article 5-Style Guarantee’ for Ukraine Makes Little Sense

At a press conference in Oslo on 20 October, Ukrainian President Volodymyr Zelensky said that he and US President Donald Trump’s envoy, Steve Witkoff, had discussed options for an American security guarantee for Ukraine. One of the prime contenders, according to Zelensky, is a bilateral US security guarantee modelled after NATO’s Article 5 collective defence provision – an idea Witkoff himself initially floated in August 2025. An alleged version of this ‘Article 5-style guarantee’ appeared in US media in late 2025. European leaders subsequently incorporated a similar concept into their own proposed security guarantees.

Something is getting lost in translation. The notion that the US and European nations would obligate themselves to defend Ukraine from a future Russian attack – the essence of Article 5 – strains credulity. A pledge by Trump to do so would be especially implausible considering how his administration has cut American support for Ukraine and is intent on reducing the US role in Europe’s security. But even European leaders or a future US president who is more supportive of Kyiv would be challenged to make an ‘Article 5-style’ commitment appear credible, at least not without a proven willingness to become more directly involved in Ukraine’s defence.

A more realistic course would be for the US and Europe to commit, through a set of legally codified agreements, to a steady supply of weapons, training, defence industrial cooperation, and intelligence sharing for at least a decade after the war ends. Doing so would ensure that Ukraine in peacetime has the financial, material, and technological resources to build and maintain a credible armed force that can blunt a Russian attack, along with a suite of long-range capabilities that can hold at risk critical targets inside Russia. In that way, deterrence – both denial and punishment – is squarely in Ukraine’s hands rather than tangled up in an untested promise of future action from partners.

Beware the Potemkin Article 5

Ukraine wants a postwar arrangement that will deter Russia from attacking it again, even if Russia is left occupying a fifth of its territory. In that way, Ukraine might aim to replicate the American security guarantee to South Korea in the wake of the 1953 armistice that ended the Korean War, or the one West Germany received when it joined NATO in 1955. Each guarantee was backed by the long-term basing of tens of thousands of American troops in theatre, such that an adversary considering an attack would have had to contend with the strong likelihood of ending up in a direct war with the US.

Ukraine’s partners, meanwhile, have gone to great lengths to provide military, intelligence, and financial support. But no country has been willing to send combat forces to Ukraine. Even Ukraine’s staunchest supporters have turned down requests to extend air defence coverage over parts of western and southern Ukraine despite the relatively low risk that such a mission would entail.

Moreover, the prospect of a postwar deployment of foreign troops on Ukrainian soil is questionable. In spring 2025, the UK- and France-led ‘coalition of the willing’ began readying a multinational force to be sent to Ukraine after the war ends. The contributing nations have established a headquarters and are conducting their first major deployment exercise in Poland in November. But the coalition has placed such stringent conditions on a deployment – a total ceasefire, Russia’s agreement, and an explicit American backstop – that it is hard to see it ever materialising.

Why, then, have American and European officials entertained the idea of an ‘Article 5-style’ guarantee for Ukraine?

The first possible explanation is that they intend to act differently – in other words, intervene militarily – if Russia were to attack Ukraine again. But considering how far they have gone to avoid a direct war with Russia, that is hard to fathom. Recognising the disconnect, Zelensky in late October pressed his American interlocutors to explain what they would do in such a scenario: ‘What [is the US] prepared to do? In what numbers? Aviation or ground operations, if Ukraine needs to be defended quickly?’ But it is hard to see an American president (or a European leader, for that matter) committing to such specific military responses.

The second, more plausible explanation is that Washington and Europe are dangling an ‘Article 5-style’ guarantee in the hopes of never having to fulfil it, and with no intention to do so if push came to shove. They might calculate that the mere existence of the guarantee, even if worded ambiguously, would give Moscow enough pause to deter it from attacking Ukraine again. But what if Russia called their bluff? Ukraine’s partners could then take a highly legalistic approach to interpreting their commitments, much as Trump has questioned the language of Article 5 itself: ‘There’s numerous definitions of Article 5. You know that, right?’ he told reporters in 2025.

What Makes Article 5 Credible

Trump is right, in a literal sense, that the text of the North Atlantic Treaty leaves plenty of room for NATO Allies to decide what form their response to an armed attack on another would take. And yet, NATO Allies have spent the past 77 years imbuing this admittedly vague text with significant credibility by means of forward troop deployments, an integrated command structure, military exercises, and extensive contingency planning. Russia views Article 5 as credible because of these concrete measures, not because of the treaty text.

Meanwhile, in Ukraine’s case, neither the US nor Europe has taken serious steps to prove that a commitment to defend Ukraine would be anything more than words on paper. If the US and Europe are truly willing to come to Ukraine’s defence in the future, they will have to show that they mean it; that will probably entail some form of combat presence in Ukraine and meaningful contingency planning, at a minimum. But if they are not, they would be foolish to make that promise.

A Better Option

Fortunately, Ukraine and its partners have a realistic alternative: to build up and sustain the Ukrainian armed forces as the guarantor of the country’s long-term security. Ukrainians fear that a potential ceasefire or peace settlement will prompt the West to scale back its military, intelligence, and financial support while Russia rearms, leaving Ukraine battered and vulnerable to another attack. The goal of a long-term security arrangement must be to persuade Moscow – and assure Ukrainians – that this will not happen.

This ambition is achievable because Kyiv’s partners have shown they are willing to supply it with most of the tools it needs to fight: nearly every category of advanced weapons system, battlefield intelligence, significant investments into Ukraine’s own defence production, and technical cooperation in the design and production of new long-range strike systems. Moreover, public opinion polling reveals that Ukrainians are more confident in their own country’s armed forces than in external guarantees of future intervention.

Missing from the West’s current policy is a long-term vision of what would constitute a credible Ukrainian defence and deterrence capability and a concrete, well-resourced, multiyear programme of support to get there. The bilateral security agreements signed between Ukraine and more than two dozen countries starting in 2024 were a step in the right direction. But none of the texts were legally binding, with the partial exception of the US agreement, which President Joe Biden signed under his sole executive authority with a binding obligation to consult Ukraine in case of an attack, and a slew of nonbinding provisions related to specific military aid. In any case, Trump ignored the US-Ukraine agreement when he cut most American aid in early 2025. Moreover, the two dozen other signatories of agreements with Kyiv largely treat them as political symbols, especially now that the US has withdrawn from coordinating their implementation.

Rather than agonising over phraseology about future intervention, Kyiv and its partners should revitalise and build on the existing bilateral agreements, uniting them into a single governing structure that harmonises what is now a disparate set of formats and bodies that handle planning, resources, and training. With the Trump administration likely unwilling to helm this body, the UK is in a prime position to cajole Kyiv and its other supporters to consolidate their efforts. There is a hodgepodge of structures that can be brought under this umbrella, to include the Ukraine Defense Contact Group, the ‘capability coalitions’ created under the bilateral security agreements, the NATO Security Assistance and Training for Ukraine (NSATU), the coalition of the willing, NATO’s Prioritised Ukraine Requirements List (PURL), the EU Military Assistance Mission Ukraine (EUMAM), the Anti-Ballistic Missile Coalition, and the numerous efforts to support Ukraine’s defence industry.

This governing structure – to which participating nations could send high-level envoys – should have the authority to set objectives for Ukraine’s future force and make decisions about long-term procurements that balance between foreign-supplied systems and indigenously produced ones; it should also clarify what financial, technical, and supply-chain questions must be resolved (and by whom) to build and sustain production lines in Ukraine and abroad. This governing structure should also develop contingency plans to surge additional support to Ukraine in case of an attack; for example, creating Europe-based weapons stockpiles that would be available to Ukraine in a break-glass moment would take time but would demonstrate long-term resolve. Finally, this arrangement should be codified as a multilateral treaty or embedded within country-specific domestic legislation that cannot be easily ignored or overturned.

Building an enduring security arrangement along these lines is doable because it is based on policies that Ukraine’s partners have already determined to be in their national interests. Fighting on Ukraine’s behalf is, on the other hand, something they have ruled out for now. It is time for Kyiv and its partners to abandon the fiction of recreating Article 5 and instead focus on what will deter Russia: a strong Ukrainian military, supported by partners in a coherent and sustainable manner.

© Eric Ciaramella, 2026, published by RUSI with permission of the author.

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