Paper - Belfer Center for Science and International Affairs, Harvard Kennedy School

Ukraine-NATO Primer: Membership Options Following the 2023 Annual Summit

| July 14, 2023

From July 11-12, NATO leaders gathered in Vilnius, Lithuania for one of the most significant NATO summits in history. Against a backdrop of Russia's ongoing invasion of Ukraine, 31 NATO Heads of State and partners met to address key challenges for the alliance. A central agenda item was the future of Ukraine’s NATO membership. By the culmination of the summit, the alliance chose to strengthen the NATO-Ukraine partnership but did not outline a specific timeline for Ukrainian membership. 

President Biden has shown reluctance to explicitly lay out a roadmap for Ukraine's accession, concerned that such a move could de facto imply NATO's decision to engage in a military conflict with Russia. In the lead up to the summit, President Biden said, “I don’t think [Ukraine is] ready for membership in NATO.” The summit, however, produced a new NATO-Ukraine Council, increasing ties between the alliance and the at war nation. The following serves as a background piece on Ukraine’s history with NATO, potential future pathways for accession, and the operational impact Ukraine’s NATO membership could have on the alliance. 

NATO and Ukraine’s Long Standing Relationship 

Ukraine’s independent relationship with the U.S. and Russia was formalized just three years after the dissolution of the Soviet Union. In December 1994, leaders of the U.S., the United Kingdom, and the Russian Federation met in Budapest, Hungary, to pledge security assurances to Ukraine. The signature of the Budapest Memorandum concluded arduous negotiations that resulted in Ukraine’s agreement to relinquish the world’s third-largest nuclear arsenal in exchange for security guarantees. 

Three years later, the NATO-Ukraine Commission (NUC) was established in July 1997 by the NATO-Ukraine Charter on a Distinctive Partnership. The NUC has been the primary mechanism to develop the NATO-Ukraine relationship. 

Over ten years later at the 2008 NATO summit in Bucharest, Romania, Ukrainian leadership sent a letter trying to secure a pathway to membership. Ukraine requested that NATO leaders extend a Membership Action Plan (MAP) - the traditional first step in joining the alliance. A MAP is a customized program providing guidance and hands-on-assistance tailored to aspiring NATO nations. Ukraine requesting a MAP in 2008 was the nation’s first attempt to secure membership. NATO did not offer a MAP to Ukraine or to Georgia, which also sought NATO membership that year. Vocal pushback from several western and central European leaders, stemming from a fear of antagonizing Russia, was a roadblock to Ukraine’s NATO membership in 2008. Ultimately, a NATO communiqué at the summit did confirm that Georgia and Ukraine would eventually be welcomed as NATO members.

Following the Bucharest Summit, Ukraine has marched steadily and purposefully toward meeting NATO membership standards with the hope of membership. In the years since the annexation of Crimea by Russia in 2014, Ukraine has ensured their domestic laws, including their Constitution, and international commitments adhere to NATO policies. 

On September 30, 2022, Ukraine formally submitted an application for NATO membership. In June 2023, Ukrainian President Volodymyr Zelensky acknowledged membership would likely not be offered during the war but, on July 1, 2023, he stated, “At the Vilnius Summit, we need a very concrete and clear signal that Ukraine could become, and has the right to become, an equal member of NATO after the war.” Despite a confirmation of eventual membership at the Vilnius Summit, NATO still did not indicate a membership timeline. When the summit failed to outline a timeline for membership, Zelensky called it “unprecedented and absurd.” 

Process for NATO Accession 

There are two key dimensions for Ukraine’s accession into NATO: the process and the timeline. At the summit in Vilnius, NATO agreed to exempt Ukraine from the traditional process, but did not further define the timeline. 

Before officially joining NATO, partner nations are traditionally offered a MAP, which serves as an accession process tailored to each nation. The MAP includes five key areas: political and economic issues, defense/military issues, resource issues, security issues, and legal issues. Throughout this process, aspiring NATO members seek to meet standards for each issue area and utilize NATO advice and support to do so. Universal MAP criteria are not specifically defined for NATO membership, but instead crafted for each country as part of the process to meet the broad democratic and security standards of NATO. The MAP can be a lengthy process; in the eighth enlargement of NATO, the Republic of North Macedonia participated in MAP for 21 years before finally joining in 2020. A Ukrainian MAP could possibly set concrete goals for resilient institution building and good governance practices that heed to NATO standards to address criticism of historical corruption.

Despite the precedent for MAP as a precursor to NATO membership, NATO Secretary General Jens Stoltenberg stated the alliance would exempt Ukraine from the MAP. The alliance expanded without a MAP when Finland, the newest NATO member, did not have to execute the process. After application to NATO on May 18, 2022, NATO signed Finland’s accession protocol on July 5, 2022. Less than a year after their application process began, Finland formally became a member of NATO on April 4, 2023. Stoltenberg argues a battle-tested Ukraine already armed with NATO equipment would not need to go through the standard process. Given concerns over democratization, however, Ukraine’s accession process may still follow MAP-like guidelines and principles even if the MAP process is not formally applied.

The timing of Ukraine’s accession to NATO is increasingly constrained by rapidly developing geopolitical interests. While Ukraine could join NATO during the ongoing war with Russia, Ukraine joining the alliance during the invasion is extremely unlikely as NATO leadership worry Western troops could be drawn into a direct conflict with Russian forces. As Article 5 of the NATO treaty stipulates collective defense where an attack against one member is considered an attack against the entire block, Ukrainian NATO membership could result in NATO troops in the Donbas. 

The timeline, however, remains one of the predominant impasses for NATO consensus as smaller states continue to call for entry immediately. Some analysts counter that “frozen conflicts” were not a barrier to NATO membership when originally created, citing West Germany’s accession in 1955 after its status as an occupied country came to an end. Additionally, waiting until the end of the war brings risk, as some warn Russia would likely avoid signing any peace agreement to further stall Ukraine’s membership to NATO. 

For both the membership pathway and the timeline, NATO unanimous support is required. All NATO action requires unanimous consent of its members. Any one nation could derail well laid plans for Ukraine joining NATO, which was demonstrated when Turkey announced their fleeting intent to block Sweden’s bid for NATO membership. Given Turkey’s ties to Russia, it is possible they could attempt to delay the expansion of the alliance again or extract substantial concessions from European states in exchange for supporting Ukraine’s accession. Thus far, however, Turkey has outwardly remained supportive of NATO membership, with President Erdogan saying, "There is no doubt that Ukraine deserves NATO membership." 

Position of NATO Allies  

Former Soviet States that are now NATO members have been resolute in demanding immediate Ukrainian membership in NATO. Latvia’s Prime Minister led the call saying, “the only chance for peace in Europe is when Ukraine will be in NATO.” Ahead of the Vilnius summit, Lithuanian Prime Minister Ingrida Simonyte stated, "It would be very sad if in any way anyone could read the outcome of the Vilnius summit as a victory of Russia in precluding Ukraine to join NATO one day.”

NATO Secretary-General Jens Stoltenberg said in April 2023, that, “All NATO Allies have agreed that Ukraine will become a member,” and, “Ukraine’s future is in NATO.” However, one month later, Stoltenberg cautioned that although Ukraine would eventually join the alliance, becoming a member “in the midst of a war is not the agenda.” Stoltenberg will remain a definitive voice on this issue as, days ahead of the Vilnius Conference, it was announced that his leadership of NATO was extended by one year.

Despite nations' reluctance to explicitly state it, an underlying worry persists that granting Ukraine NATO membership might incite Russia, draw Western troops into the conflict, or divert attention away from empowering Ukraine’s war efforts. The U.S. and Germany have been the two most prominent NATO members hesitating to act on Ukraine’s membership during Russia’s invasion. German Chancellor Olaf Scholz has stated, “nobody can become a member of a defensive alliance (NATO) during a war.” 

The UK lies somewhere between a hesitant Germany and the determined Baltics, arguing for expedited Ukrainian membership after the war. UK Foreign Secretary James Cleverly stated, the UK would support, “[moving on] from the membership action plan, recognizing that the offer to Sweden and Finland didn’t require that, and Ukrainians have demonstrated their commitment to reform the military for the requirement of NATO membership through their actions on the battlefield.” 

The Impact of NATO Membership to Ukraine 

In the very unlikely scenario that Ukraine joins NATO during the war, what would the potential impact be? First, Article 5 would assuredly be invoked, but the makeup of boots on the ground may look very similar to their posture now. Article 5 affirms that each state must take, “such action as it deems necessary … to maintain security.” When Article 5 was invoked following 9/11, not every NATO nation sent troops to Afghanistan. 

Thus, if Ukraine joined NATO during the war, each Ally could define how it satisfies collective defense; Article 5 invocation doesn’t necessarily mean every nation would commit troops to a war with Russia, and countries could maintain their current levels of bilateral support. Western states would likely remain reluctant to send troops or air power into direct confrontation with Russia. The near-term battlefield impact would not likely be significantly different from the present level of support provided by individual states. NATO has very few organic military capabilities and relies entirely on the voluntary contributions and capabilities of its member states. While each Ally must meet certain minimum military standards to be admitted as a member, once admitted there is no real authority or mechanism within the alliance to compel members to take any specific action.

In the short term, NATO membership likely would resemble the current levels of bilateral support. Robust supply lines and extensive intelligence sharing agreements have developed since the start of the war and support Ukrainian front line operations. If Ukraine joins NATO after the war, Ukraine could increase defense interoperability and enhance intelligence sharing with all NATO members in the long-term.  

The value of NATO membership is that it provides a framework for NATO Allies to collaborate and negotiate. Admitting Ukraine as a member would give them a seat at the table, likely elevating their ability to influence the Allies within the system to provide additional support. In the future, this certainly would have an impact to negotiate with the Allies for more support within the NATO Alliance architecture. Ukraine’s membership could also help each state with their own domestic political and budgetary agendas, as there may be greater domestic political will to support Ukraine as a NATO Ally rather than on a bilateral basis.

Beyond the battlefield, NATO membership would likely provide a framework for Ukraine to continue democratic reforms. The accession of Ukraine into NATO will certainly force the nation to address long-running issues with corruption in the defense establishment and security services. With or without a formal MAP process, the scrutiny of Ukraine’s membership in NATO will likely require Ukraine to meet the alliance’s aspirational democratic standards and may force continued reform in these areas. 

The Impact of Ukrainian Membership to NATO 

Ukraine isn’t the only actor that seeks to benefit from NATO membership: the NATO alliance could benefit as well. Ukraine is leading the way in tactics for conventional warfare, as well as employing emerging technology such as drones and AI on the battlefield. As the U.S. plans for a possible confrontation with China over Taiwan, the West can learn from the largest conventional attack since WWII. Furthermore, NATO can capitalize on its investment in Ukraine’s army and fortify its eastern flank. Military aid to Ukraine wouldn’t be going to an Ally, but to the alliance itself.

Beyond the borders of Europe, Ukrainian membership in NATO would likely send a geopolitical message that the West stands strongly for a rules-based international order. NATO membership demonstrates a strong pushback against unilateral acts of war that goes beyond significant aid and arms support. Russia’s invasion of Ukraine has highlighted the key role of NATO in defending the liberal international order and other actors, including China, are assuredly watching to see the resolve of the 74 year old alliance. 

Alternative to NATO Membership 

If NATO cannot agree on a timeline for Ukrainian membership, some argue for an “Israel Model” for Ukraine. This model of partnership mirrors the U.S.-Israel relationship by prioritizing arms, training, and military support, along with security assurances. Rather than a formal NATO treaty, this proposal would rely on more ambiguous, non-legally binding agreements. The U.S. has provided written security assurances to Israel, and NATO member states could provide either bilateral or multilateral security assurances to Ukraine. The model is not without risks, but is more politically feasible in the short-term than full NATO membership. 

Way Ahead 

During the Vilnius Summit, Ukraine's Allies signaled their intention to offer long-term security assurances and confirmed that Ukraine will eventually be a member of NATO. President Biden further announced, “the members of the G7 are launching a joint declaration of support for Ukraine … [we’re] going to help Ukraine build a strong, capable defense across land, air and sea, which will be a force of stability in the region and deter against any and all threats.” Additionally, bilateral aid will continue to flow from most NATO nations to Ukraine, and future bilateral security commitments will enhance security assurances. 

With an upgraded NATO-Ukraine Council and a promise Ukraine will not have to execute a MAP, Ukraine’s NATO membership seems inevitable. Without a timeline for accession or a clear end to Russia’s invasion in sight, however, it is highly uncertain when Ukraine will join the alliance.

For more information on this publication: Belfer Communications Office
For Academic Citation: Rosenbach, Eric, Grace Jones and Olivia Leiwant. “Ukraine-NATO Primer: Membership Options Following the 2023 Annual Summit.” Paper, Belfer Center for Science and International Affairs, Harvard Kennedy School, July 14, 2023.

The Authors

Eric Rosenbach