With Russian tanks having rolled over its borders, what could give Ukraine security in the postwar period? That is the question being debated in the capitals of allied nations ahead of Nato’s Vilnius summit in July.

For Ukraine, there is one ideal solution to ensure its security: full Nato membership, as first promised in 2008 and bringing with it the alliance’s Article 5 mutual defence pact. Though President Volodymyr Zelenskyy this month acknowledged Nato accession to be “impossible” while the war rages, Kyiv has nonetheless been lobbying strongly for the summit to incorporate a roadmap, invitation or explicit commitments on Ukrainian accession and security guarantees along the way. Zelenskyy has even threatened not to attend Vilnius should there not be such a “signal” on Ukraine’s future place in Nato. 

However, the Ukrainian leader is likely to be disappointed. The alliance is proving divided over the issue — the UK, Poland and the Baltic states are supporting calls for Ukraine’s accession while others like Germany have been more reluctant to open talks. 

With Nato accession a distant prospect at best, the question remains as to what postwar security arrangement to offer Ukraine instead. One proposal put forward is the “Kyiv Security Compact”, an idea developed by former Nato secretary general Anders Fogh Rasmussen and Zelenskyy’s office, whereby a group of allied countries would invest heavily in Ukraine’s defence capabilities and make binding security commitments under bilateral agreements. 

For his part, French President Emmanuel Macron has overcome his former hesitation regarding Ukraine’s accession to Nato to advocate “something between Israel-style security guarantees” — a reference to the extensive weapons and support given to Israel by the US — and actual Nato membership. However, these are very different concepts: Nato membership entails direct intervention in the event of attack, while Israel-style support does not. 

As Macron’s remarks demonstrate, vagueness is a danger stalking these discussions about security guarantees. Another risk is that, given the delays and disagreements surrounding the issue, nations may take matters into their own hands, creating a confused patchwork of arrangements which could even escalate the conflict. This month, Rasmussen noted that, in the absence of a clear path for Ukraine’s Nato accession, “some countries individually might take action”, with Poland and the Baltic states possibly putting troops on Ukrainian territory as a “coalition of the willing”.   

Indeed, the most significant issue is how to create an arrangement which could realistically deter Russia. France, Germany, the US and UK are reportedly now preparing an umbrella political declaration under which they and Ukraine would conclude bilateral agreements for multi-year supplies of military and financial assistance, the overall goal being to render Ukraine too difficult to invade again. However, this “security guarantee” may prove neither secure nor guaranteed. 

Neither the declaration nor the bilateral agreements would have the status of legal treaties and they would be outside the Nato framework, entailing no direct military intervention should Russia decide it fancies a rematch. Assurances have proven worthless in the past, Ukraine having surrendered its nuclear weapons in return for promises of protection from Russia, the US and the UK under the 1994 Budapest Memorandum. 

Ukrainian Deputy Prime Minister for European Integration Olha Stefanishyna has complained that “Ukraine is the most experienced country in the world in hearing ‘no’ from NATO”. The Vilnius summit is unlikely to be any different, with Nato allies procrastinating and prevaricating over Ukraine’s membership since 2008. That ambiguity, offering Ukraine the security of Nato membership at some vague future juncture, encouraged Vladimir Putin. The confusion now surrounding Ukraine’s future security arrangements may embolden him again.