Its Security Depends on Long-Term Commitments From the West
The U.S. Congress’s approval last month of a $61 billion aid package for Ukraine came not a minute too soon. Ammunition shortages resulting from Washington’s months-long dysfunction have eroded Ukrainian frontline positions and left cities and critical infrastructure exposed to missile and drone barrages. Top military and intelligence officials in Kyiv have advised Ukrainians to brace for territorial setbacks in the coming months. Already, the Russian military has stepped up pressure on Kharkiv, forcing thousands of Ukrainians to flee out of fear that Russian forces could soon reoccupy their towns.
The infusion of U.S. aid should help Ukraine stabilize the front and protect its skies. But the Ukrainian army also urgently needs more soldiers. Indecision in Kyiv over a new mobilization drive has left combat units severely undermanned, their losses exacerbated by a failure to build defensive fortifications last year and by Russia’s widening firepower advantage. Military experts believe that the Ukrainian army needs to triple its intake of recruits to sustain defensive operations at current levels of fighting. Kyiv is trying to fix its manpower shortage and has asked its NATO partners to help train recruits inside Ukraine. This would be a faster and more effective way to prepare Ukrainian soldiers for battle. Most countries, including the United States, have refused to deploy trainers on Ukrainian soil out of concern for their safety, but Kyiv’s dire battlefield position might be prompting some of them to reconsider.
Critical as they are, additional U.S. weapons and Ukrainian personnel will only serve as a bandage to stop the bleeding. A deeper problem remains: the lack of a coherent strategy to confront the long-term threat that Russia poses to Ukraine—and to European security. For more than two years, Kyiv and its partners have operated in crisis-management mode, planning in increments of months rather than years.
But this short-term approach is no longer fit for purpose—nor is it sustainable. By now, it should be clear that there is no shortcut to ending this war, be it on the battlefield or through political and economic pressure on Moscow. Ukraine, with the help of the United States and others, will thus need a strategic vision that revolves around enhancing its defense capabilities and rebuilding deterrence over the long term. U.S. Secretary of State Antony Blinken’s announcement in Kyiv on May 14 that the United States plans to sign a ten-year bilateral security agreement with Ukraine is a step in the right direction. Alongside similar agreements Kyiv has signed with several other partners, it would signal to Russia that even though Ukraine is unlikely to join NATO any time soon, the United States and Europe have its back.
But even more can be done to develop a coherent long-term security strategy for Ukraine. Deterring Russian aggression will require three elements: denial, punishment, and credibility. To deny Russia’s ability to win on the battlefield, Ukraine must build up its armed forces and defense industry so that it can field and sustain capabilities that both degrade Russia’s military capacity and make a future Russian invasion unlikely to succeed. To signal the threat of punishment, Western militaries must devise contingency plans to impose meaningful costs on Russia if it attacks Ukraine again after a hypothetical cease-fire agreement is reached. And to make these plans credible in Moscow’s eyes, Western nations must commit, ideally in legally binding form, to resourcing them. That’s where Ukraine’s security agreements with the United States and other NATO allies, if implemented and resourced properly, will be critical.
Achieving a durable peace will be impossible without a clear vision for Ukraine’s long-term security. The Kremlin must understand that its goal of subjugating Kyiv is not achievable—not now, and not ever. Only then might the Russian leadership come to the table for meaningful talks—and accept Ukraine’s independence in the long run.
DON’T STOP THINKING ABOUT TOMORROW
In the summer of 2022, Ukraine and the United States began to scope out a long-term plan to equip the Ukrainian armed forces with a credible defense and deterrence capability. The dramatic opening phase of the war had just ended. Russia’s blitzkrieg had failed, and Ukraine successfully defended its independence. Kyiv’s partners began pulling advanced weaponry from their stockpiles to aid in what was shaping up to be a grinding battle for the east of the country. In short order, Ukraine learned to operate and maintain dozens of different types of foreign equipment.
The Biden administration realized early on that this emergency approach had its shortcomings. The threat from Russia was unlikely to fade, and Kyiv had to begin planning for a long war. U.S. military planners ran thousands of simulations of the war’s trajectory and developed models for Ukraine’s “future force,” as the concept became known. The goals of this exercise were twofold: to manage costs by standardizing equipment, and to make decisions about the capabilities Ukraine would need over the long haul even while it was still fighting.
Unfortunately, this planning took a back seat as the war entered a new phase. In the fall of 2022, Ukraine notched victories in Kherson and around Kharkiv. Those triumphs shifted the focus from building the future force to training and equipping Ukrainian troops for a large-scale offensive in 2023. But despite extensive preparation, Ukrainian forces were unable to penetrate Russia’s well-fortified frontlines.
By now, it should be clear that there is no shortcut to ending this war.
Since 2022, Russia has marshaled its economy for wartime production and has found ways to shield itself from Western sanctions. Artillery shells from North Korea, attack drones from Iran, and technical components from China have aided Russia’s military reconstitution and battlefield performance. As a result, since early 2024, Russia has made slow but steady gains along the frontlines, particularly around Donetsk, where its wins have come at a high cost.
Now that Kyiv is set to receive U.S. aid that will help it minimize further losses this year, the conversation must shift back to the long term. Building Ukraine’s future force will require systematic military planning, prioritization of objectives, and predictable Western support over an extended period. It will also require tough conversations about war aims, tradeoffs, and timing, all of which have implications for the cost and sustainability of the force.
IN DEFENSE OF DEFENSE
Ukraine’s rearmament should be tied to a clear military strategy. Should Kyiv be able to generate a force capable of complex combined-arms offensive operations, with the objective of liberating territory occupied by Russia? Or should the goals be more modest: defending the frontline as it now stands, protecting major population centers, degrading Russian combat capabilities, and deterring a future full-scale attack?
The first model is attractive because it energizes Ukrainians, most of whom still want to retake occupied territory and free their fellow citizens from Russian rule. It also allows Western leaders to present a clear theory of victory to their constituents. But it may not be realistic, at least not for the next several years. Ukraine’s military has shown agility and competence in many areas but will require much more field training, staff development, and equipment to be able to conduct synchronized operations at and above the brigade level. This scale of training, a prerequisite for a successful push against deep defensive lines, will be next to impossible to conduct while all of Ukraine’s combat power is committed to fighting in the east. Moreover, a larger, heavier offensive force will be costlier to build and sustain over time.
A force built to defend and deter, on the other hand, would be more affordable. Ukraine cannot directly match all of Russia’s capabilities, but it need not do so to impose costs effectively. With the right suite of tailored capabilities, it can mitigate or, where possible, counterbalance Russia’s advantages in most domains. For example, Russia has a clear advantage in airpower. Ukraine must be equipped to protect its skies with layered and integrated ground-based air defenses and a nimble fourth-generation air force. At the same time, it should be able to threaten key military and economic targets inside Russia. Western nations should provide capital investments and technical expertise for Ukraine’s nascent long-range strike drone program, which has scored remarkable hits on military installations deep inside Russia.
A strategy to build up Ukraine’s long-range strike arsenal would serve three purposes. First, it would enable Kyiv to systematically target Russia’s force regeneration and weapons production facilities, degrading Moscow’s ability to wage war. Second, it would contribute to deterring future Russian aggression by raising the costs that Moscow would suffer if it attacked again. And third, it would have the potential to compel Moscow to scale back its air and missile attacks on Ukrainian civilian populations and critical infrastructure.
Ukraine’s Black Sea campaign is an example of the type of deterrence that is possible. Kyiv’s employment of long-range fires, armed drones, and undersea capabilities against Russia’s naval assets in and around Crimea forced Russia’s Black Sea Fleet back from Ukraine’s coast and allowed for the reopening of the economically vital port of Odesa. Russia might make a similar calculation in its air campaign if it judges that Ukraine has enough firepower to hurt it in a symmetrical manner.
MESSAGE FOR MOSCOW
Ukraine argues that only NATO membership offers the kind of ironclad security guarantees that will end the war and deter another Russian invasion. But the alliance is not ready to offer an invitation—and probably will not be until after an extended period of peace. Still, the United States and its allies must ensure that Ukraine will be able to defend itself during this interim period. To do so, they should codify commitments to finance, train, and equip Ukraine’s future force and credibly signal that they will surge weapons—and potentially even employ their own assets—if Russia attacks Ukraine again.
Last July, the G-7 powers and Ukraine declared their intent to forge a latticework of bilateral security commitments designed to lock in Western support for the long haul. Two dozen other nations have since joined the declaration, and nine nations have signed ten-year security agreements with Ukraine. The United States is now negotiating its own. These agreements, although nonbinding, are good news for Kyiv. They show a degree of political commitment to Ukraine’s security that dwarfs previous Western assurances, including those in the Budapest Memorandum of 1994 that led to the removal of Ukraine’s Soviet-inherited nuclear arsenal.
There are four key ways that Kyiv and its partners can turn these agreements into a coherent long-term security arrangement. The NATO summit in Washington this July offers an opportunity to advance the conversation on all four fronts. First, Ukraine and the signatories of the agreements should develop a shared concept of Ukraine’s future force. Some of this work has already begun in the multinational working groups, known as “capability coalitions,” that have been tasked to look at Ukraine’s military requirements in several areas, from armor and air defense to maritime security and airpower. Kyiv and its partners should consider appointing a council of senior envoys to oversee this effort, culminating in a report by the end of 2024 that offers a detailed procurement and training plan for Ukraine’s military over the next decade.
Second, Ukraine’s partners should announce a dedicated fund for the future force that is cabined off from current operations. Most allies have announced their funding for 2024, with vague commitments for future years. But without predictable multiyear financing, fulfilling Ukraine’s acute battlefield needs will always take priority over future investments.
Ukraine’s rearmament should be tied to a clear military strategy.
Putting a price tag on the future force will not be easy. A starting point would be the defense budget of Poland, a country with a population and threat environment similar to Ukraine’s. NATO Secretary-General Jens Stoltenberg’s proposal for a $100 billion, five-year fund for Ukraine is on the scale of what is needed for the future force. Some of this funding should be reserved for incentivizing Ukrainian and Western firms to pursue joint ventures, for localizing production and training inside Ukraine, and for hardening Ukraine’s defense industrial base against physical attacks. These steps would lessen Kyiv’s reliance on foreign support over time.
Third, it is not too early for Ukraine’s partners to start discussing what they would do in case the country is attacked again—after a hypothetical cease-fire, armistice, or settlement. So far, they have committed to consulting with Kyiv and providing “swift and sustained” support. For these statements to be a credible signal to Moscow, they must be backed up by actions. The allies could agree, for example, to create a “Ukraine war reserve stock” of weapons and ammunition on NATO territory that would be surged to Ukraine in such a scenario. They also could launch a study of how NATO’s own defense and deterrence posture could be adjusted to complicate Moscow’s calculus in a hypothetical attack on Ukraine.
More assertive options, such as deploying troops to Ukraine in noncombat roles or providing air defense coverage over parts of Ukraine near NATO territory, will be a tough sell while the war is ongoing. But they should be on the table if there is a cease-fire. Developing robust plans for the West to enforce a cease-fire is a plausible way to signal to Moscow that it cannot expect to attack Ukraine again without suffering even more severe consequences. It also would go a long way toward helping Ukrainians feel confident that opting for a cease-fire at some point would not leave them defenseless while Russia rearms.
Finally, the United States should lead its allies in codifying these long-term commitments in a way that is credible and will weather electoral cycles. The U.S. Congress’s bipartisan vote on Ukraine aid shows how this can be done: the margins in favor in both the Senate and House were well above what would be needed to approve a treaty or a regular statute. As the Biden administration continues its negotiations with Kyiv on a bilateral agreement, it should begin a serious dialogue with leaders in Congress about the U.S. strategy to defeat Russia’s aggression and how it should be resourced in the coming years. Far from serving as a blank check to Ukraine, a legislatively ratified policy that is based on a bipartisan, interbranch consensus would ensure predictability, sustainability, proper oversight, and greater leverage to demand that allies share responsibility for supporting Ukraine.
THE WAITING GAME
There is no silver bullet to end Russia’s war against Ukraine. Russian President Vladimir Putin is committed to his dual goals of imposing his will on Kyiv and rewriting the rules of European security. He believes that time is on his side and feels little pressure to compromise, even with new U.S. aid flowing into Ukraine. In these circumstances, constructing a diplomatic pathway to reach a settlement is putting the cart before the horse.
It could be a long time—years, maybe even decades—before Ukraine has a realistic shot at regaining all of the territory Russia occupies, whether by military means or through diplomacy. But Putin is not immortal, his regime is not eternal, and his war has created internal pressures that could manifest in destabilizing ways. For centuries, the Russian state has undergone cycles of external expansion and chaotic retrenchment. The last time Moscow was on its back foot, in 1991, Ukrainians played their hand brilliantly and won their independence. When the window opens again, Ukraine should be ready to use it for maximum advantage.
In the meantime, Ukraine needs strong Western security commitments. Ukrainians must have the confidence that they will have their partners’ support no matter what course the war takes—even if they decide one day that pursuing a cease-fire is in their interest. And the Russian leadership must understand that its leverage over Kyiv will continue to shrink as Ukraine’s capabilities grow, backed by an unshakeable Western commitment to the country’s long-term security. Whether one believes the war will end on the battlefield or at the negotiating table, a strategy to build Ukraine’s defense and deterrence capacity while signaling the West’s staying power is the best way to create a durable peace in Europe.