NATO membership for Ukraine: The only lasting deterrence against future Russian aggression

In the weeks after the North Atlantic Treaty Organization’s (NATO) summit in Vilnius, a seemingly off-hand comment by NATO Secretary-General Jens Stoltenberg’s chief of staff, Stian Jenssen, unleashed a brief storm of controversy. Speaking at a conference in Norway in mid-August, Jenssen suggested that Ukraine’s membership in the North Atlantic Alliance might require giving up some of its territory to Russia to end the war. As could have been expected, Jenssen’s remarks deeply frustrated the Ukrainian government. Foreign Minister Dmytro Kuleba promptly clarified that Ukraine will not consider relinquishing its territories at the expense of joining NATO. The advisor to the President’s Office, Mykhailo Podolyak, simply called the suggestion ridiculous. Despite Jenssen’s subsequent apologies and assurances by other NATO officials that the Alliance continues to stand strongly behind Ukraine’s territorial integrity, the prospects for the country’s membership still remain unclear.

Stuck in strategic ambiguity, the Ukrainian government is increasingly looking for solid security guarantees that will ensure sustainable peace and deterrence from renewed Russian aggression whenever the war ends and until Ukraine becomes a NATO member. Kyiv learned a tough lesson from Russia’s complete disregard for its commitments under the Budapest Memorandum, which was supposed to act as the main international instrument to ensure Ukraine’s territorial integrity and sovereignty. In 1994, the Russian Federation, United Kingdom, and United States committed inter alia to respect the existing borders of Ukraine and refrain from threats or uses of force in exchange for Kyiv giving up any claims to the Soviet-era nuclear weapons left on its territory, which would have made Ukraine the third-largest nuclear power in the world. Since then, however, Russia has consistently undermined Ukrainian sovereignty in both militarily overt and “hybrid” ways, culminating in the full-scale invasion launched in February 2022.

Recently, President Volodymyr Zelenskyy’s chief of staff, Andriy Yermak, stated that Kyiv had begun consultations with Washington on the provision of security guarantees to Ukraine. Yermak soon followed that up with another statement revealing that similar negotiations were underway with London, in a bid to have security arrangements in place by the end of the year. And a few days ago, Ukrainian Defense Minister Rustem Umerov met with U.S. Defense Secretary Lloyd Austin to discuss weapons assistance and Ukraine’s security guarantees, among other topics. These proactive bilateral moves with key Western supporters followed the outcome of NATO’s Vilnius Summit, where Ukrainian expectations of a formal invitation or specific timeline to join the Alliance failed to materialize.

The wording of the Vilnius Summit’s final joint communiqué sparked much controversy, even though an invitation for Ukraine to join NATO was never on the agenda. Broadly, the allies seemed to be in agreement that Ukraine could join NATO only after the war with Russia ends. U.S. National Security Advisor Jake Sullivan reiterated this position clearly at the NATO Public Forum. According to Sullivan, Ukraine’s accession to the Alliance while the conflict continues to rage would automatically mean that NATO was suddenly at war with Russia. Despite allied unity and renewed promises to support Ukraine for as long as it takes, NATO has been consistently reiterating that it is not engaged directly in a war with Moscow. Thus, the only relatively clear precondition that Ukraine received at the Vilnius Summit was that the membership accession process could not begin until the war is over.

The ambiguity of the language used in the final communiqué echoes the Bucharest Summit of 2008, where the allies agreed that Ukraine (and Georgia) would eventually become members of NATO but did not provide any timeframe. Since then, the false beliefs that it is possible to coexist peacefully with Vladimir Putin’s Russia have been left in the past. Following the Bucharest Summit, Russia invaded Georgia in August 2008, annexed Crimea and sparked a purportedly “separatist” war in eastern Ukraine in spring 2014, and is now waging a genocidal war of conquest against Ukraine. The absence of any security guarantees for Ukraine since Bucharest emboldened Putin to pursue his ambitious goals. The only form of deterrence that has unquestionably stopped Putinist Russia’s revanchist military operations in the region has been NATO’s Article V collective security umbrella. Despite numerous reckless threats and aggressive rhetoric toward a number of frontline NATO members, Putin for now has always acted below the threshold of Article V vis-à-vis those states.

Russian officials have repeatedly warned Finland and Sweden against joining NATO and pledged that serious military and political consequences would follow. The deputy chair of Russia’s Security Council, Dmitry Medvedev, went as far as to threaten that Moscow would redeploy nuclear weapons closer to Finland’s and Sweden’s borders. However, the best defense toward any potential Russian threat is precisely joining the Alliance and coming under Article V protection. Acknowledging this, Helsinki and Stockholm changed their long-standing non-alignment policies and decided to seek NATO membership as soon as possible; Finland was admitted at Vilnius, while Sweden will join as soon as Turkey completes its ratification process.

The Vilnius Summit theoretically shortened Ukraine’s path toward NATO by removing the requirement for a Membership Action Plan (MAP). And allies agreed on the establishment of a NATO-Ukraine Council to support Ukraine’s Euro-Atlantic integration as well as improve coordination between the Alliance’s members and Ukraine on an equal level. Moreover, the recent summit resulted in increased commitments of military and financial aid; at the same time, the G7 countries announced long-term bilateral security commitments for Ukraine. Still, as important as it is for Ukraine to work with individual partners and receive their long-term support, the key security guarantor for Ukraine can only be NATO and its Article V umbrella. No arrangement other than full NATO membership will entirely remove the threat of a Russian re-invasion, at least so long as Putin remains in power.

So despite the fair disappointment over the lack of clarity on accession, Zelenskyy still managed to wring some tangible results out of the Vilnius Summit. Yet with the membership dilemma unresolved, mixed messages from NATO officials, such as the aforementioned comment from Jenssen, do not help. Medvedev was quick to mockingly state in response that in order to join the Alliance, Ukraine will need to give up Kyiv itself — “the capital of Ancient Rus [sic].” As long as Russia believes that NATO membership is a distant prospect for Ukraine, it will seek to inflict as much damage as possible on the latter, until Kyiv submits and the West loses its nerve. Security guarantees and bilateral defense cooperation frameworks with Western allies are important, but the only long-term and sustainable means to secure Ukraine is full NATO membership.

Natia Seskuria is an associate fellow at the Royal United Services Institute (RUSI) and was previously a fellow with MEI’s Black Sea Program.

Photo by Artur Widak/NurPhoto via Getty Images