What Military Forces Are Needed to Ensure Ukraine’s Security?

Since taking office, Donald Trump has dashed any hope for Ukraine to continue receiving significant aid from the United States. Given the remaining combat capability of its army and the U.S. pressure to bring an end to hostilities, President Zelensky fully understands that he will have to come to the negotiating table. He is requesting to be supported by the European countries backing him and to receive strong security guarantees from his Western allies. Specifically, he is calling for a force of 200,000 soldiers.

Definition of the Mission and the Structure of This Force

There could be two possible missions:

• A monitoring force for the front line and the ceasefire. This would resemble the UNIFIL mission, deployed since 1978 on the border between Lebanon and Israel, with the task, among others, of “monitoring the cessation of hostilities” and a contingent of 13,000 troops. In practice, the monitoring mission has been largely reduced to counting rockets, aircraft, and tanks passing by and reporting back to New York. A more limited version of this, consisting of unarmed civilians, was the OSCE Special Monitoring Mission in Ukraine, which, as has been evident since 2022, failed to produce meaningful results.

• A security mission, meaning the defense of Ukraine, designed first to deter Russia from attacking and, if an attack occurs, to repel it decisively. This force must be capable of forceful action. Given the lessons learned from three years of war against Russian forces, a contingent of 200,000 soldiers, structured within a determined and well-equipped organization—including armored vehicles, artillery, drones, aircraft, munitions, cyber defense and cyberattack capabilities, and a robust logistical chain—would be the minimum requirement. This would be equivalent in size and equipment to the entire current French army.

Volunteers, Step Forward

Who can provide this force capable of sustained combat over time, ensuring troop rotations or even stationing soldiers with their families in Ukraine? The political constraints are well known: no American units, no NATO command structure. So, who remains?

The European countries that have supported Ukraine and have spent three years promising to do everything to protect it (as evidenced by numerous signed security agreements) are the obvious candidates. If not, could the involvement of third-party actors be considered?

Among European nations, Poland and Germany—both undergoing military rearmament—are credible military actors, yet they lack the political will to take this step. France, before making its decision, must consider its unique status as a nuclear power and reflect on the link between its vital interests and nuclear deterrence. There may be a few other willing participants, some of whom were not invited to this meeting in Paris.

The hidden side of support for Ukraine

Regarding the very idea of a European force in Ukraine, it is worth recalling some events from 2021 to reflect on this question. That year, Russia conducted a large-scale military exercise, ZAPAD 2021. Meanwhile, Western nations carried out various exercises in Ukraine, all clearly focused on defending the country against a potential Russian invasion. The most significant was Exercise Sea Breeze in June, co-organized by NATO, the United States, and Ukraine. It brought together 32 countries from six continents, with 5,000 troops, 32 ships, 40 aircraft, and 18 special operations teams, all united by their firm commitment to defending Ukraine against Russia:
“NATO supports Ukraine’s sovereignty and territorial integrity within its internationally recognized borders, extending to its territorial waters.”

Three key observations emerge: just days before 22 February 2022, all countries and NATO members with a military presence in Ukraine withdrew their forces; none of the participants in Sea Breeze applied the expertise gained during the exercise by sending troops to support the Ukrainian army; and out of the 42 countries involved, six (including major powers) have not enforced the sanctions imposed by the United States or the EU against Russia.

Which Third-Party Actors?

If Europe reaches an impasse, a few actors, driven by the ambition to gain international status and accepted by both Moscow and Washington, could step in to form a purely symbolic force. Turkey, which has already played a role through its attempts at a peaceful resolution of the conflict, or Saudi Arabia, which is set to host the negotiations, could be candidates. China, currently on standby, might also seek to establish a foothold in Europe while reinforcing its “no-limits friendship” with Russia. While the United States would undoubtedly reject this solution, China cannot afford to remain without a proposal.

Additionally, it remains uncertain whether the countries that traditionally participate in UN operations will step forward. Given the current geopolitical climate, there is no guarantee, as Russia appears to be gaining more favor in the Global South.

Towards a Dual Framework for Security Guarantees

The first framework includes the European Union, which, albeit reluctantly, could manage to gather a small contingent of soldiers as a symbolic demonstration of its commitment, acknowledging that it cannot offer more in terms of military capability (a modified version of solution 1).

The second, more substantial framework is based on satisfying the two major powers that have clashed on this battlefield. For Russia, this would mean control over Donbas and Crimea, along with the initiation of a European security conference to address its security concerns. For the United States, it would involve an agreement with Ukraine for reconstruction efforts and the exploitation of the country’s resources in exchange for an American security guarantee.

In President Trump’s vision, this security guarantee would not rely on military force but rather on the revival of strategic dialogue between the United States and Russia. The goal would be to reconcile their long-term, or even very long-term, interests and to end a century of conflict, particularly as the specter of Chinese hegemony looms on the horizon.

From Malta to Riyadh: A Lesson in Strategy

To those in Europe who grumble about being sidelined, it is worth recalling the meeting between George H. W. Bush and Mikhail Gorbachev in Malta on December 2–3, 1989. That summit, held without Europe’s direct involvement, marked the end of the Cold War and the beginning of negotiations on disarmament and security in Europe. A meeting between Donald Trump and Vladimir Putin in Riyadh could be no less ambitious. It will then be up to their successors to carry forward this momentum.

The European Union, which has not fully grasped the mechanisms that led to the war in Ukraine, may be frustrated at being excluded from this process. However, much like after the Malta summit, it will still reap the benefits.

It must now start considering how to safeguard and build upon those gains.