Ukrainian President Volodymyr Zelensky at a press conference with NATO Secretary-General Jens Stoltenberg, Kyiv, Ukraine, September 2023
Ukrainian President Volodymyr Zelensky at a press conference with NATO Secretary-General Jens Stoltenberg, Kyiv, Ukraine, September 2023
Gleb Garanich / Reuters

As the second anniversary of Russia’s invasion of Ukraine draws near, Kyiv’s allies are struggling to articulate a common vision for the long-term security of Ukraine and of Europe. The invasion, and the Ukrainian people’s subsequent courageous resistance, appeared to be a watershed moment for the transatlantic alliance—underscoring its value and illuminating Ukraine’s importance to Europe. NATO mobilized troops to its eastern flank, Europe and the United States offered Kyiv unprecedented aid, and Europeans stepped up to host millions of Ukrainian refugees.

But two years later, both the shock prompted by Russian President Vladimir Putin’s aggression and the awe at Ukraine’s fighting spirit seem to have worn off. The July 2023 NATO summit in Vilnius exemplified the shift in mood. The gathering rightfully celebrated Finland’s historic accession, but it also exposed deep rifts between NATO allies on whether to admit Ukraine. Despite a concerted effort by the Baltic states and Poland to push the alliance to offer Ukraine membership, the summit failed to yield such an invitation, instead settling on an ambiguously worded communiqué declaring that NATO could invite Ukraine to join “when Allies agree and conditions are met.”

NATO must not make the same mistake in 2024. The absence of a clear plan for Ukraine to join NATO has given Putin more confidence that he can wait out the West and defeat Ukraine in a war of attrition. Moreover, the lack of resolve on NATO membership sends all the wrong signals about the West’s own confidence in Ukraine’s ability to win, which makes policymakers more reticent to approve large military assistance packages. NATO’s ambiguity sets up a feedback loop whereby Kyiv’s purported failures—driven, to a large degree, by a lack of adequate Western military aid and lags in the delivery of support—appear to offer evidence that further support in the form of NATO membership would be of little use or might even backfire, forcing the West to become more directly involved in the war. But Russia’s ability to improve its logistics and fighting in recent months is, in part, a result of NATO’s ambivalence. Putting Ukraine on the path to NATO accession is no symbolic matter: it is the country’s best hope to prevent Russian aggression in the long run.

It is also the best way to strengthen NATO’s deterrence capabilities and its value as an alliance. Some analysts may fear that the alliance’s Article 5 provision would require Washington and its allies to join the war more directly. But Article 5 does not automatically commit the alliance to enter the war. Rather, it stipulates that the alliance determines “action as it deems necessary,” which may or may not include putting troops on the ground. And Putin has long framed the war against Ukraine as a war against NATO and the West. So whether Ukraine’s Western allies like it or not, the world, including China, would see Ukraine’s subjugation by Moscow as a defeat for NATO, with profound global consequences for U.S. global leadership and for international security. This summer, NATO must move to make things right, asserting that the only possible path to durable peace in Europe starts with putting Ukraine on a clear path toward membership.

PARADISE LOST

In late 2021, as Russia amassed forces on Ukraine’s eastern borders, U.S. intelligence officials began warning Europe and Ukraine about Moscow’s intention to attack. These intelligence assessments correctly identified Moscow’s strategic objectives as political: Putin wished to subjugate Ukraine through military force, thereby keeping Ukraine in Russia’s sphere of influence and preventing it from further integration with the West.

From February 2022 through the summer of 2023, Ukraine’s battlefield triumphs—built on the extraordinary military and financial assistance from the United States and its NATO allies—created a sense that momentum was on Ukraine’s side. Kyiv did not fall to Russian troops in three days, as Putin hoped and as many in the West feared. In fact, the Ukrainian military pushed back Russia’s advances in four regions Putin claimed to have annexed and, in the winter of 2022–23, successfully withstood numerous missile attacks against military and civilian infrastructure. Ukrainian President Volodymyr Zelensky became the face of courage, successfully lobbying European and American policymakers to provide Ukraine with over $200 billion in military, economic, and humanitarian assistance.

Heading into the 2023 NATO summit in Vilnius, the Ukrainian leadership hoped to gain a formal invitation to join NATO. But without the United States on board, that effort stalled. U.S. President Joe Biden has firmly maintained since 2022 that while the alliance would defend “every single inch of NATO territory,” he saw direct NATO engagement in Ukraine as a path to World War III, which is why the United States had to find workarounds to coordinate military assistance from NATO member states in the U.S.-led “Ramstein format.”

The hope that Ukraine can trade land for peace is a fantasy.

NATO member states on the alliance’s eastern flank nonetheless consistently worked to push the United States to provide Ukraine with a clear path to accession. Their argument was that the alliance had to telegraph to Russia that continuing the war would not prevent NATO’s enlargement. And if Ukraine fell under Russia’s control, a hostile state would share a border with Hungary, Poland, Romania, and Slovakia—NATO territory that the Kremlin still sees as belonging to Russia’s sphere of influence. But fears of escalation won out over this long-term strategic vision.

To some degree, Ukraine then became the victim of its own success. The country’s political and military achievements in the first year of the war surpassed all expectations, setting tremendously high hopes for the 2023 counteroffensive. When Yevgeny Prigozhin, the head of the Wagner paramilitary group, launched his June 2023 mutiny, Putin looked even weaker. As preparations for the counteroffensive began, Western policymakers started carefully calibrating the amounts and types of weapons they would provide Kyiv, fearing that overwhelming Ukrainian successes could provoke a desperate Putin to use tactical nuclear weapons.

To be sure, Ukraine achieved important successes in the second half of 2023. It pushed Russia’s fleet in the Black Sea further east, enabling Kyiv to resume its grain exports. But optimism has now flagged with respect to what Ukraine can achieve militarily. It is an open question whether the United States will sustain its support for Kyiv, and if it does not, Europeans will not be able to fill the gap. Amid the growing belief that little territory will change hands during 2024, some analysts and politicians are calling for a cease-fire, followed by negotiations in which Ukraine would be expected to cede territory to Russia.

But obtaining any peace deal—much less one that would be enduring—will be a huge challenge. Thanks to China, Iran, and North Korea, Russia has replenished its drone and missile stocks and is terrorizing Ukrainian civilians with increasingly aggressive attacks. Putin has shown no indication that he would compromise with Kyiv. Previous attempts to engage Russia diplomatically on the future of Ukraine have been failures, revealing that the Kremlin is not interested in negotiating seriously. Most important, Russia’s strategic objectives have not changed. Putin evidently still wishes to subjugate all of Ukraine, not occupy a portion of the country’s territory. The idea that Ukraine can trade land for peace and thus remain free on the land it controls is a fantasy.

TUNNEL VISION

Biden has indicated that NATO will not formally invite Ukraine to join the alliance at its upcoming July summit in Washington. Those who believe that extending Ukraine a NATO invitation would be a mistake claim that the country’s accession would only worsen the binds in which Europe and the entire West now find themselves. They say that Russia will not or cannot pose a serious threat to existing NATO allies but that adding Ukraine to the alliance would increase the risk of a direct NATO-Russian war. They assert that if Ukraine joined NATO, allies would have to declare war on Russia as a consequence of Article 5—and if they did not, Article 5 would be revealed to be toothless, dangerously undermining the alliance’s deterrence value.

These arguments are wrong. While it is at war, Ukraine will certainly not join NATO. And the critics of a Ukrainian accession are correct that NATO needs to consider how it would uphold Article 5 if conditions allow Ukrainian membership to go forward. Only the territory that Ukraine holds at the end of the war would be covered by Article 5, even if the West refuses to formally recognize Russian-held territory as part of the Russian Federation. NATO would need to beef up its military presence on its eastern flank and add rotating troop deployments into Ukraine to deter further Russian military attacks, including drone and missile attacks against civilians.

The war in Ukraine has already demonstrated that NATO membership deters Russian attacks.

But these tasks are well worth undertaking—indeed, they are necessary. At its July summit, NATO will have to determine how to prevent Russia from continually threatening Ukraine in the long term, a scenario that would in turn give Moscow carte blanche to foment perpetual instability in Europe. The experience of the past three decades indicates that offering NATO membership to Ukraine would help deter Russian aggression, not prompt it. For now, Moscow sees states left in the “gray zone” between NATO and Russia as ripe for military incursions in ways that NATO members are not. If the alliance fails to move beyond the 2023 Vilnius summit declaration, its hesitation will motivate Putin to keep pursuing the war in Ukraine—to prevent it from joining NATO—and even, potentially, to attack other non-NATO states such as Moldova.

Some critics also argue that creating a formal accession process for Ukraine is unnecessary given the overall robustness of Western support for Kyiv. Accession to NATO would not materially change Ukraine’s short-term military prospects, this argument goes, but it would needlessly aggravate Putin. The war in Ukraine, however, has already demonstrated that NATO membership deters Russian military attacks on member states’ territory. Putin knows full well where the supplies inflicting high casualties on his troops come from. And yet he has not attacked NATO territory to prevent resupply efforts. Like Biden and European leaders, he does not want a NATO-Russian war.

By providing significant military, economic, and humanitarian support since February 2022, NATO has shown that it understands how deleterious a Russian victory over Ukraine would be for Europe’s long-term security. A Russian takeover of Ukraine—demonstrating the failure of Western deterrence—would vastly increase the likelihood that war in Europe will expand beyond Ukraine. Russian imperialism is today the greatest threat to European security. Putin has made it clear that he is not content with Russia’s internationally recognized 1991 borders, and he has again and again publicly stated an expansive vision of what territory properly belongs to Moscow. His imperialist vision appears to have broad popular support in Russia. Putin has put his country on a war footing, and he is already rebuilding his military. The return of Russian aggression is inevitable even if a temporary cease-fire puts the current situation on ice.

ELEVENTH HOUR

NATO membership is the only long-term means Kyiv has to deter future Russian attacks. Ukraine has recently inked valuable bilateral security assistance agreements with Canada, the United Kingdom, and other countries, but these will not be enough. If Russia ends up controlling any part of Ukraine’s territory—an outcome that the West should continue to work to avoid—the lands under Kyiv’s control must be secured by being anchored in NATO. The concern that Ukrainian membership in NATO will create instability by threatening Russia has the problem backward: the failure to include Ukraine in NATO would leave the Russian threat to Ukraine and Europe intact for the foreseeable future.

The 2024 NATO summit is also an opportunity for Biden to lock in his Ukraine policy’s successes before the United States’ 2024 presidential election. These successes could be erased by a second Donald Trump presidency unless NATO moves toward institutionalizing its commitment to Ukraine’s security. This institutionalization benefits the United States: paradoxically, integrating Ukraine into NATO reduces the likelihood that the U.S. military will become overextended. NATO’s military planners estimate that it will take three to five years for Russia to rebuild and modernize its military into a more sophisticated force than it was before 2022. If Russia is not deterred, a renewal of its militarism could coincide with a confrontation between the United States and China over Taiwan.

NATO does not need to offer Ukraine an immediate formal invitation. It can announce that it is opening accession talks with an invitation to follow at a future date, as the European Union has done with Ukraine regarding EU membership. But as NATO representatives and the alliance’s heads of state and government gather in Washington, there must be a broad recognition that Ukraine should be a part of NATO as soon as it meets specifically stated requirements, particularly on defense sector reforms. In terms of preparedness, Ukraine already has the most capable army in Europe, with a battle-tested force that would become an asset, not a liability, to the alliance. Without strong concrete action by NATO at the upcoming summit demonstrating that Ukraine’s future is in the alliance, the situation in Ukraine is likely to continue to erode in Moscow’s favor—with profound negative consequences for Europe and the United States.

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  • ALINA POLYAKOVA is President and CEO of the Center for European Policy Analysis and Donald Marron Senior Fellow at the Henry A. Kissinger Center for Global Affairs at the Johns Hopkins University’s School of Advanced International Studies.
  • JAMES GOLDGEIER is a Visiting Scholar at Stanford University’s Center for International Security and Cooperation, a Visiting Fellow at the Brookings Institution, and Professor of International Relations at American University.
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