by Steven Pifer
For some 20 years after regaining its independence in 1991, Ukraine wavered in how far to take its relationship with NATO. That changed following Russia’s illegal seizure of Crimea and engagement in fighting in Donbas in 2014. Ukraine’s leaders and people increasingly came to view the alliance as the best answer for their country’s security needs.
A growing number of NATO allies support Ukraine’s membership as important for Europe’s security and are ready to extend Kyiv an invitation to join. Other allies, however, are reluctant to take that step now, particularly while Ukraine remains at war with Russia.
Division within NATO over this issue broke into the open in the run-up to the alliance’s July 2023 summit in Vilnius. Allies seemed determined to avoid a repeat at the July 2024 summit in Washington. That summit described Ukraine’s path to membership as “irreversible,” and NATO decisions focused on providing Kyiv the military wherewithal to defend itself against Russia’s continuing assaults. The “when” of Ukraine’s membership remains a question for the future.
How Far with NATO?
In the early years of its independence, Kyiv sought to build relations with the West to balance an often-overbearing Russian neighbor. In January 1994, Ukraine became one of the first former Soviet and former Warsaw Pact states to join NATO’s Partnership for Peace, which aimed to develop political and military cooperation between NATO and countries to its east.
As discussion within NATO of possible enlargement began, Kyiv saw countries on its western border—Poland and Hungary—angling for membership but was uncertain how far to go in its own relationship with the alliance. US diplomacy helped address the question, suggesting that, as NATO proceeded with enlargement and developed a NATO-Russia relationship, it also develop a partnership with Ukraine. In 1997, NATO and Ukraine established a distinctive partnership to promote regular consultation and cooperation.
In early 2002, Ukraine announced its intention to seek membership. Kyiv apparently had noted a warming trend in NATO-Russia relations and figured the announcement would not provoke Moscow. In the event, Ukraine did not pursue the kinds of reforms—political and economic as well as military—that NATO expected of aspiring members. It was not a serious bid.
When Victor Yushchenko became president in 2005, he articulated the goal of drawing closer to NATO. In January 2008, he asked NATO to grant Ukraine a membership action plan (MAP) when alliance leaders held a summit in Bucharest in April. At that point, Ukraine arguably had made as much progress on meeting NATO norms as had some other countries when they received MAPs. However, allies could not reach consensus. The summit communique stated that Ukraine “will become” a member, without offering Kyiv a MAP for doing so.
In 2010, Victor Yanukovych, elected as Ukraine’s fourth president, sought to improve relations with Russia and made clear that he had no interest in bringing Ukraine closer to NATO. His government favored a “non-bloc” policy barring membership in any military alliance, which Ukraine’s Rada (parliament) formalized in law. Ukrainian public opinion at that time showed little interest in alliance membership.
Following the Maidan Revolution in February 2014, Yanukovych fled Ukraine as Russian forces moved to seize Crimea. Russia annexed Crimea that March. One month later, Russian security and military personnel fueled fighting in Donbas in eastern Ukraine. By the end of 2014, Petro Poroshenko, elected president in May, and his parliamentary faction favored NATO membership. The Rada overwhelmingly voted to repeal the “non-bloc” law. In early 2019, with Russian forces continuing to occupy Crimea and part of Donbas, the Rada amended the constitution to make European Union and NATO membership a strategic goal.
Volodymyr Zelensky became president in May 2019 and confirmed the strategic goals of EU and NATO membership. He requested a MAP in 2020 and, following the Russian invasion in 2022, pressed for accelerated admission. Opinion polls confirmed that the government’s push for NATO membership enjoyed the support of an overwhelming majority of Ukrainians. One survey showed that public approval for entering NATO climbed to 89% in May 2023.
Apart from the membership issue, NATO members and the alliance itself began providing significant financial and military assistance to Ukraine following Russia’s 2022 invasion. They started with man-portable anti-armor and anti-aircraft weapons. By 2024, allies were sending Ukraine heavy artillery, advanced air defense systems, modern main battle tanks and other armor, and rockets that could strike targets at ranges of some 300 kilometers.
Vilnius Summit and the Article 5 Question
In the run-up to the NATO summit in Vilnius in July 2023, a number of allies, including Poland, the Baltic and Nordic states, France, and Britain, proposed that Ukraine be invited to join. However, other allies, most notably the United States and Germany, were not prepared to agree to extend an invitation. The alliance’s internal division on the issue broke into the open on the eve of the meeting, and Zelensky voiced displeasure that there would be no invitation.
The Vilnius summit communique reaffirmed Ukraine’s future in NATO and stated the country had moved past the need for a MAP. The language added that [NATO leaders] “will be in a position to extend an invitation to Ukraine to join the alliance when allies agree and conditions are met”—a formulation that elicited little happiness in Kyiv. In parallel, G7 leaders announced that they would negotiate bilateral security commitments to ensure that Kyiv had forces capable of defending the country in the near term and deterring a new Russian attack in the future. They invited non-G7 countries to negotiate such agreements as well.
Ukraine today meets many requirements for alliance membership, though it still has more to do, for example, in the areas of security service reform, anti-corruption measures, and reducing the influence of the country’s oligarchs. Those questions are now addressed in the NATO-Ukraine Council, established in Vilnius. Ukraine has shown it would not be just a “consumer” of NATO security; it can offer the alliance a battle-hardened military.
The larger issue regarding membership, however, turns on Article 5 of the NATO Treaty, which states that an attack on one will be considered an attack on all. Are alliance members prepared to commit to go to war against Russia on Ukraine’s behalf? NATO Secretary General Jens Stoltenberg has observed that Ukraine joining NATO is an issue for after its current war with Russia. That likely reflects his judgment that no alliance consensus on inviting Ukraine to join will prove possible while it is at war. Ukrainian membership under those circumstances would confront allies with the Article 5 question of entering the war against Russia with their own military forces. That would be a difficult decision to make in 32 NATO capitals.
Bringing a Ukraine at peace into the alliance would offer a much different and easier dynamic. In that case, the Kremlin would face the difficult decision of whether to go to war again with Ukraine, this time a member of NATO. The most likely outcome: Moscow would be deterred, just as it has been deterred from aggression against any NATO member for 75 years.
Washington Summit
Well before the Washington summit, US officials stressed to allies and Kyiv the need to avoid a repeat of the open division displayed before the Vilnius summit and made clear the United States would not agree to extend Ukraine a membership invitation at the summit. They showed little interest in other ideas, including one suggested by retired US diplomats and military officers that the summit launch accession talks with Kyiv, with an invitation to be extended later.
US and NATO officials talked of building “a bridge toward membership” for Ukraine, an idea that was incorporated into the summit communique and a separate NATO-Ukraine Council statement issued after allied leaders met with Zelensky. The documents also described Ukraine’s path to membership as “irreversible” in a bid to make Ukraine’s road to NATO more definitive—a question of when, not whether.
Instead of membership, the Washington summit’s Ukraine deliverables focused on addressing Kyiv’s near-term military needs. Allies announced the provision of one SAMP-T and four Patriot air defense batteries, the imminent arrival of F-16s, and the intention to provide “a minimum” of 40 billion Euros ($43 billion) over the next year to sustain security assistance for Ukraine. The summit communique noted the establishment of a joint NATO-Ukrainian analysis, training, and education center in Poland and the appointment of a NATO senior representative to be based in Kyiv. Allies also established the NATO Security Assistance and Training for Ukraine program, which will assume some of the role of coordinating allied assistance to Ukraine previously done by the US-organized Ukraine Defense Contact Group.
By July 11, the final day of the Washington summit, Ukraine had concluded bilateral security agreements with 23 countries and the European Union in the process launched by the G7 in 2023. The agreements generally commit countries to help Ukraine develop stronger defense capabilities and take actions supporting Ukraine in the current or a future conflict with Russia and are seen as part of the “bridge” to Ukraine’s membership in NATO.
Looking Forward
The United States has long defined a stable and secure Europe as a vital national interest. European members of NATO of course share that interest. A number of allies have concluded that Ukraine’s membership is critical for a stable and secure Europe, calculating that Europe will be unstable and less secure if Russia prevails over Ukraine, if the war drags out endlessly, or if a tense, unsteady, and fragile peace is struck between the two.
While much has been accomplished in the NATO and Western effort to support Ukraine and move it closer to the alliance since the 2022 Russian invasion, Ukrainians remain frustrated. They see their fight against Russia not only as a war to defend Ukraine but as a defense of Europe. Ukrainians are also frustrated that some Western arms come with strings attached, i.e., they cannot be used to strike targets in Russia. Getting those limits lifted was high on Zelensky’s wish list in Washington, but he did not succeed, at least not as regards US-provided weapons.
The bilateral security agreements commit important assistance to Kyiv in terms of financing, training, arms, and ammunition. However, no bilateral agreement commits a country to send its military forces to Ukraine’s defense. Ukraine remains outside any alliance structure, and a Ukraine alone could prove a temptation for Moscow to return to conflict in the future.
Uncertainty hangs over the “when” of Ukraine’s membership (even leaving aside the question of a possible return by Donald Trump to the White House in 2025). While it is not wholly excluded that Kyiv might receive an invitation even as the current war with Russia continues, that appears extremely unlikely.
Some have suggested that Article 5 might be modified, e.g., made to apply only to that part of Ukraine under Ukrainian control. However, any such dilution of Article 5 would be a mistake and would raise concern among allies on NATO’s eastern flank. It is in the interest of all NATO members, including Ukraine in the future, that Article 5 stand as stark as possible and apply to all territory of alliance members. That makes for a stronger and clearer deterrent.
While continuing to make its case for membership, Ukraine should work diligently with the NATO-Ukraine Council to implement reforms needed to bring the country into full conformity with NATO standards and norms. Kyiv should aim to be in a position so that, when a window of opportunity to join opens, it is fully ready to enter. When that will be, however, remains unclear.
Steven Pifer is affiliated with Stanford’s Center for International Security and Cooperation and the Brookings Institution. A retired Foreign Service officer, his more than 25 years with the State Department included assignments as deputy assistant secretary of state with responsibilities for Russia and Ukraine, ambassador to Ukraine, and special assistant to the president and senior director for Russia, Ukraine and Eurasia on the National Security Council. He also served at the U.S. embassies in Warsaw, Moscow and London.