Ukraine Seeks Guarantees to Prevent Another Invasion

“The guarantee of security is a strong army,” says Volodymyr Zelensky. At the same time, he acknowledges that without American weapons, which have long been in short supply, and without European financial support, such an army cannot be built.

The president does not specify what kind of weaponry Ukraine expects from the United States. Washington is already supplying dozens of categories of equipment and munitions—from ammunition and body armor to artillery. But in Kyiv, the shortage most often emphasized is that of air defense systems and the missiles that power them.

“The U.S. produces all the weapons Ukraine needs—above all artillery, missiles, air defense systems, aircraft, and armored vehicles. How this will be financed—through European funds or loans—is secondary. What matters is that the U.S. has the political will to guarantee supplies over the long term,” notes military analyst Pavel Luzin. According to him, Europe has the money to sustain Ukraine’s armed forces.

Even if Washington is willing to supply weapons, obstacles remain, notes Marina Miron, a researcher at King’s College London. The first is the risk that in the event of another invasion some of the arms could fall into Russian hands. The second is production limits: modern systems take time to build, and demand is overwhelming. “The queue for Patriot systems is enormous—they are needed, among others, by Israel. The U.S. will tell Ukraine: ‘Get in line, place your order, pay the money. You’ll get them eventually.’” The third is geopolitics: Russia, she argues, may have more to offer the U.S. than Ukraine does, while Trump tends to see Europe more as a client than an ally. And although Europe’s resources are substantial, the continent cannot arm Ukraine on its own.

Much will also depend on Ukraine itself, stresses Dmitry Gorenburg of Harvard’s Davis Center for Russian and Eurasian Studies. “The Ukrainian army can provide two types of guarantees. First—the ability to repel an invasion. Second—a deterrent effect, when Russia understands that a new war would mean heavy losses,” he says. The expert recalls that one of the reasons for the full-scale invasion in 2022 was Moscow’s confidence in an easy victory. A strong army, he argues, must strip the Kremlin of such illusions.

To ensure Ukraine’s security, allied assistance must include several key elements, according to the Center for Strategic and International Studies (CSIS).

Troop deployment. The number depends on the mission: monitoring a ceasefire would require about 6,000 troops, while creating a deep defensive posture could take more than 100,000. According to Bloomberg, around ten European countries, including Britain and France, have already expressed readiness to send soldiers. The U.S., as Donald Trump has repeatedly emphasized, will not deploy its own forces to Ukraine.

Air defense. Depriving Russia of air superiority would be one of the main tasks in the event of a new invasion. CSIS estimates that between 40 and 160 modern aircraft would be required. They might not be stationed in Ukraine itself but at bases in neighboring countries. European leaders have already discussed with Trump the idea of deploying F-35s in Romania as part of future guarantees.

Naval defense. This element, experts note, would be less costly. To ensure secure shipping in the Black Sea, Ukraine would need anti-ship missiles, naval drones, patrol boats, and aerial surveillance assets. Ukraine has already made significant progress in the field of naval drones.

Intelligence, communications, and cybersecurity. In the event of a renewed invasion, it will be critical to provide Ukraine’s armed forces with a resilient system of information exchange and reliable communications.

According to Dmitry Gorenburg of Harvard University, a foreign contingent in Ukraine would not be needed for direct participation in combat but as proof of the seriousness of security agreements: “Ukrainians have the bitter experience of agreements that were not honored. But the presence of allied troops on Ukrainian soil would be a visible signal of determination.” In addition, such a contingent would serve as an extra deterrent for Moscow.

Marina Miron of King’s College London, by contrast, doubts its effectiveness: “As I understand it, Russia has already declared that it would consider foreign troops in Ukraine a legitimate target. So the question of whether their presence would actually be a deterrent remains unresolved.”

Since Ukraine’s accession to NATO is not under discussion in the near future, Kyiv may instead conclude a series of bilateral agreements with allies. According to Donald Trump’s special envoy Steve Witkoff, these could be modeled on Article Five of NATO’s founding treaty.

That article states that an attack on one or more members of the alliance is considered an attack on all. Yet the wording leaves room for interpretation: assistance may be provided “by taking forthwith, individually and in concert with the other parties, such action as it deems necessary.”

It is precisely this ambiguity that raises doubts, notes Marina Miron of King’s College London. “Collective defense does not mean the automatic deployment of troops to a neighboring country. Allies could simply say: ‘We’ll help you. We’ll condemn Russia. We’ll impose sanctions. Or we’ll send ammunition. Good luck!’ For me, such agreements are more a tool of diplomatic maneuvering than a real guarantee,” she says.

According to Moscow, the prospect of Western security guarantees still seems remote. Last week Sergey Lavrov reminded that Russia supports the proposals discussed during the 2022 negotiations, which included Ukraine’s neutral status and limits on the size and weaponry of its armed forces. He described discussions on security without Russia’s participation as utopian, and the deployment of foreign troops in Ukraine as unacceptable.

Moscow’s consent to Western guarantees would represent a major concession, but today the Kremlin is not ready for compromise, notes Dmitry Gorenburg of Harvard University. In his view, over the past two months Russia’s main goal in negotiations has been to buy time for continued fighting and to ease the pressure of new U.S. sanctions.

One possible form of guarantees, according to Marina Miron of King’s College London, could be the deployment of peacekeepers involving troops from all five permanent members of the UN Security Council—the U.S., the U.K., France, Russia, and China. But Moscow’s participation makes the idea nearly unworkable: Volodymyr Zelensky has already stated that Russian involvement in any guarantees for Kyiv is out of the question. Asked how Ukraine might be forced to accept it, Miron replied: “Ukraine doesn’t really have a choice, because it is losing the war. The issue is not who is right, but who is stronger.”