What Could Security Guarantees for Ukraine Look Like?

After the failure of the Budapest Memorandum, Ukraine is seeking new security mechanisms with clear commitments from partners. But will they be strong enough to make future aggression impossible?

After nearly four years of full-scale war, it has become clear: a return to the model of the Budapest Memorandum is impossible. Ukraine will no longer agree to declarative documents without clear mechanisms of action. That is why one of the main priorities of Ukrainian diplomacy today is the formation of a new system of security guarantees for the post-war period. This process is underway both through negotiations with key partners at the level of military staffs and political leaders and within the framework of a “coalition of the willing,” which already includes more than 30 countries. The goal of these guarantees is simple yet strategic – to prevent the recurrence of armed aggression against Ukraine by making its cost prohibitively high for Russia.

What Diplomatic Guarantees Are Being Considered: A “Article 5” Model for Ukraine

President Volodymyr Zelenskyy has explicitly stated that security guarantees must be “like NATO’s Article 5.” This implies an automatic response from partners in the event of new aggression against Ukraine. The focus is on concluding bilateral and multilateral agreements that clearly outline the timelines and formats of actions by guarantor countries. Such mechanisms are already being developed: for example, the “Compact” has initiated the process of signing bilateral security agreements, with the United Kingdom, France, Germany, Italy, Canada, and the United States joining in.

The total number of countries in this coalition has reached over 30, creating a unique precedent of international partnership for a non-NATO state. However, these security agreements have so far outlined mechanisms for providing Ukraine with military and other assistance. Security guarantee agreements, on the other hand, must include clear algorithms for action in the event of new aggression against Ukraine.

The Key Issue Is Maintaining the Combat Capability of the Ukrainian Army

No diplomatic formulas will work without a strong army. That is why security guarantees include long-term funding packages for the Ukrainian Armed Forces. In 2026 alone, Ukraine will need $120 billion for defense needs. Even after the end of the active phase of the war, defense needs will not significantly decrease in the initial years. It will be necessary to demobilize part of the soldiers, create reserves of weapons and ammunition, and establish a reservist system.

These funds are allocated not only for weapons procurement but also for training military personnel: as of mid-2025, over 120,000 Ukrainian soldiers have undergone training in NATO countries. Such systematic efforts create conditions where, even in the event of a new escalation, Ukraine will have a combat-ready army from the very first days of the conflict.

Investments in Ukraine’s Defense-Industrial Complex Are Under Discussion

The development of its own defense industry is a key element of security. In 2025, Ukraine continued to allocate a significant portion of its budget to the defense-industrial complex (DIC). Over 300 new production facilities for manufacturing ammunition and drones have already been established, and dozens of contracts have been signed with global companies – from Rheinmetall in Germany to Baykar in Turkey

Ukraine’s DIC produces tens of thousands of FPV drones, hundreds of armored vehicles, and 155 mm artillery ammunition monthly. In parallel, a program to create “Defense City” – an industrial park that will unite dozens of factories in one territory – is being implemented. This scale positions Ukraine as a contributor to collective defense in Europe.

The Possibility of Foreign Troop Presence and Joint Patrols Is Being Explored

Although the deployment of foreign troops in Ukraine is not yet a primary component of the guarantees, this option is being actively discussed. Scenarios include stabilization forces of 10,000–15,000 personnel, which could be stationed in border regions or perform training missions. Additionally, the format of joint air patrols – similar to NATO’s Baltic Air Policing in the Baltic states – is under discussion. A similar initiative could operate over Ukraine’s western regions and the Black Sea waters.

Transparent Financing Is Also Part of the Guarantees: The Danish Model of Financial Assistance to Ukraine

A notable example of innovation in guarantees is the Danish funding model. Denmark became the first country to create a special Ukraine Fund, which accumulates both public and private contributions. In 2023–2024 alone, this fund provided over €1.8 billion in aid, of which €1.2 billion was directed to military support. The uniqueness of this model lies in its long-term approach. Copenhagen approved funding for several years in advance. The Netherlands, Norway, the Czech Republic, and other countries are planning to join this model. For Ukraine, this means a stable flow of resources, and for donors, it ensures transparency and control over their use.

A Model for Ensuring Air Security and Ukraine’s Integration into European Air Defense Is Under Discussion

Russia launches over 1,000 drones and approximately 300 missiles of various types at Ukraine monthly. In 2024–2025, Kyiv managed to shoot down over 80% of them thanks to Patriot, IRIS-T, NASAMS, and SAMP/T systems, but these systems are most effective when integrated into a joint network. That is why Ukraine is gradually integrating into the European air defense system. This involves creating a “shield belt” from the Baltic to the Black Sea. German IRIS-T, Italian-French SAMP/T, and American Patriot systems are already operational in Ukraine. The next step is production integration.

Special Attention Is Paid to Black Sea Maritime Security

The Black Sea has become one of the key theaters of modern warfare. Ukrainian drones and missiles have forced the Russian fleet to withdraw from Sevastopol, but the threat of a maritime route blockade remains. In 2022, when Russia blocked Ukrainian ports, global grain prices rose by 30–40%, creating a risk of famine in African and Middle Eastern countries. That is why future security guarantees will include joint actions with partners – Türkiye, the United Kingdom, Romania, and Bulgaria. This involves coordinating maritime patrols, demining the waters, and protecting trade convoys. 

NATO is already conducting Sea Breeze exercises with over 20 ships from various countries. The next step could be the creation of joint Black Sea stabilization forces to ensure freedom of navigation. This component of security guarantees is no less important than air defense: maritime routes are critical for the export of Ukrainian grain and metals, and thus for global food and economic stability.

Guarantees Will Only Work in Combination

No single tool can fully ensure security. However, their comprehensive combination – diplomatic agreements, long-term army funding, investments in the defense industry, the presence of allies, the Danish funding model, integrated air defense, and Black Sea maritime cooperation – creates a system in which renewed aggression against Ukraine becomes practically impossible. For the West, this is not just about supporting Kyiv but also about its own security: if Russian aggression goes unchecked, it will inevitably spread further. That is why security guarantees for Ukraine are an investment in the stability of all of Europe.

Igor Popov, head of United Ukraine Think Tank, expert on political and security issues