THE NOTION of security guarantees has become critical to efforts to secure a sustainable peace in Ukraine. The country demands robust guarantees and—short of fast-track NATO membership, which is no longer on the table—could settle for a strong Western military presence on its soil. The Trump administration has made clear there will be no “US boots on the ground”, strongly suggesting a European force instead. Europeans have indicated a readiness to provide such assurances but insist on some form of American backstop to deter Russia from testing the force—an option not endorsed by Donald Trump. In addition, Europe is asking America to keep forces on NATO’s eastern flank, should troops be moved to Ukraine, and for NATO to provide command and control. Russia, for its part, has signalled hostility to any Western or NATO presence in Ukraine but could live with UN-type peacekeepers monitoring the ceasefire. How to reconcile these positions?
Clearly there are many difficult issues, from territorial control and elections to war reparations and the future of sanctions. But it is security guarantees that increasingly look like the key that could unlock negotiations. Without such guarantees, Ukraine will be extremely reluctant to agree to any ceasefire or “peace deal”. As the likely sole providers of such guarantees, the Europeans have regained some leverage in the process. They maintain that European security starts in Ukraine and are therefore more inclined than America to deploy troops to stabilise the conflict and help Ukraine avoid post-war instability.
Those countries ready to give such assurances, including combat troops, legitimately expect to influence a “peace” that should be fair and sustainable. Those providing troops can also hope to benefit from a degree of reassurance from allies that are not directly involved, including America, should Vladimir Putin decide to test the guarantees or threaten those providing them.
In the short term, such a deployment will have a negative impact on NATO’s defence posture by mobilising significant resources, and therefore on allies’ efforts to strengthen defence plans. It will, however, improve European security. As part of any negotiation, Russia can be informed about the nature of the security guarantees but should not be allowed a veto over their design or implementation. Its reluctance or willingness to accept such guarantees will be a test of its good faith in the negotiations.
Regarding the practicalities of a presence in Ukraine, the European debate is rightly moving away from the misleading term of “peacekeepers”, or the concept of a small “tripwire” force, to the idea of a more capable “reassurance” force—possibly in addition to peacekeepers or observers provided by others. The point of this larger force would be to prevent a resumption of fighting by significantly raising the costs and risks of restarting the war for Russia. An American or NATO backstop mechanism could enhance the credibility and deterrent effect of such a force, and encourage more European countries to participate.
According to planners in London and Paris, a well-equipped land presence with armour and air defences, bringing together 15,000-20,000 European soldiers—operating alongside a Ukrainian army not limited in size or capabilities, as Russia demands—could be sufficient for the task. Moreover, it would not need to be deployed near the front line. This would represent a big commitment on the part of Europe as such missions typically require three times the number of troops who are deployed at any given time: one unit deployed, one returning and one preparing to deploy.
The force would need air cover capable of enforcing a no-fly-zone over Ukrainian-held territory. Provided from outside Ukraine, this support would be as important as the land force to the success of the mission. Naval assets could also contribute from the Black Sea. The rules of engagement for these forces should be clear: they must be allowed to use force should they be tested or if Russia breaks the ceasefire.
Arguably the most complicated issue is the command-and-control arrangements for the force. The size and complexity of the operation point to using NATO headquarters rather than the more limited command-and-control capabilities of the EU or individual participating countries. The most efficient approach would be a NATO operation that did not have to involve all members—as happened in Libya in 2011—but benefited from the alliance’s full command-and-control, intelligence and logistical support.
Another option would be an EU operation under the quarter-century-old “Berlin+” arrangement between the bloc and NATO, similar to Operation Althea, in the military deployment to Bosnia-Herzegovina since 2004. In this construct, the NATO command structure supports the operation, a European flag officer at the Supreme Headquarters Allied Powers Europe serves as commanding officer in charge, and the EU wields political oversight.
A third option is a makeshift command arrangement supporting a coalition of the willing. This may be easier to achieve politically but there are several drawbacks that make the operation more demanding and dangerous: for instance, access to intelligence and command-and-control assets would be more ad hoc, and possibly more constrained. And NATO could still get dragged into a conflict if Russia were to target the forces or territory of participating states.
Whatever model is chosen, there will be political headwinds. America remains reluctant to provide a backstop through NATO and fears being dragged into a conflict. Its possible unwillingness to provide critical intelligence to Ukraine and the European reassurance force after the conflict ends—ominously, it said this week that it would pause intelligence-sharing with Ukraine—creates added uncertainty and vulnerabilities. Russia has yet to accept a substantial Western presence in Ukraine that could limit its ability to turn the screw on its neighbour. Many Europeans are hesitant to take the wheel with America in the back seat, or not even in the vehicle. The Ukrainians themselves know that securing such a force would probably mean having to make concessions on others fronts.
It is, however, the ultimate test of the goodwill of all parties. Does America want a sustainable peace or just a quick, fragile fix on Russian terms? Can Russia accept a force that would hamper its ability to resume combat? Do Europeans mean it when they say that their continent’s security starts in Ukraine and that they stand ready to do the heavy lifting? Is Ukraine really ready to stop fighting if properly reassured? The security-guarantees debate is calling everyone’s bluff. ■
Camille Grand was an assistant secretary-general of NATO from 2016 to 2022. He is a Distinguished Policy Fellow at the European Council on Foreign Relations.