What is Ukraine’s best security guarantee?

Russia’s unprovoked and unjustified war on Ukraine has run nearly seven weeks. Defeated in its effort to take Kyiv, the Russian army has withdrawn from northern Ukraine and is orienting itself toward a new offensive in Donbas in the country’s east.

Moscow thus far has not engaged in serious negotiations, and revelations about the massacres of civilians by Russian forces likely have hardened attitudes in Kyiv. Still, Ukrainian President Volodymyr Zelensky has made clear his readiness to seek a settlement to end the fighting. He has offered to accept neutrality, provided that a neutral Ukraine receives security guarantees. If things reach that point, Kyiv will want to seek the right security guarantees.

The West should leave the specifics of any settlement to Zelensky and his government. They must balance their desire to end the killing of Ukrainians, the importance of positions of principle and concessions that could prove controversial with their public in deciding what terms would constitute an acceptable agreement. No one else can make that decision.

Ukraine’s partners should not press Kyiv to accept a bad deal. Nor should they urge Kyiv to reject an agreement that it believes meets Ukraine’s interests. Western officials should, however, talk to their Ukrainian counterparts about those elements of a possible settlement that implicate Western commitments. One such issue is security guarantees.

Ukraine needs more than a security guarantee just from Moscow. The Russian government committed in the 1994 Budapest Memorandum on Security Assurances “to respect the independence and sovereignty and existing borders of Ukraine” and “to refrain from the threat or use of force” against Ukraine.

Russian President Vladimir Putin shredded those commitments.

The Ukrainians desire guarantees from Western countries, though they have outlined different kinds of guarantees. One would commit guarantors to employ their military forces to defend a neutral Ukraine if it were invaded in the future — similar to NATO’s Article 5 guarantee (an attack on one is consider an attack on all).

An alternative version of the guarantees would require that guarantor states commit, in the event of an attack on a future neutral Ukraine, to immediately provide arms to the Ukrainian military and impose severe sanctions on the attacker (presumably Russia).

U.S. and NATO leaders have plainly stated their unwillingness to send troops to defend Ukraine against Russia. That makes it difficult to imagine Western countries giving Ukraine an Article 5-type guarantee as part of a settlement agreement. For the guarantee to have teeth, it would need a guarantor with credible military power, such as the United States. (Indeed, any NATO member prepared to consider offering such a guarantee likely would not do so without Washington.)

Were the Biden administration to agree to such a guarantee, that almost certainly would require a treaty. That would need a two-thirds vote in the Senate for consent to ratification. Suppose both happened. Even then, how much confidence could Kyiv have in that guarantee if, say, Donald Trump returned to the White House?

Rather than seeking guarantees from others to defend it in the event of a future Russian invasion, guarantees of uncertain value, it might be smarter for Kyiv to seek to guarantee its own security. This would mean avoiding settlement provisions strictly limiting the size and arms of Ukraine’s military. (If necessary at the negotiating table, Kyiv might consider forgoing long-range offensive strike systems, but it should protect its ability to maintain a strong defense force.)

If Zelensky finds himself in a serious negotiation, instead of asking the United States and other European countries for Article 5-type guarantees, he should seek commitments from those states to take immediate steps to help rebuild and modernize the Ukrainian military. This should go well beyond providing legacy arms from Soviet times. There would be no reason why Ukrainian military personnel could not learn how to operate and maintain some of the more modern weapons systems now in the inventories of NATO member armed forces.

Kyiv likely would find its Western partners more ready to make and fulfill such commitments, as an alternative to committing themselves to a possible future war with Russia. If asked, Washington should indicate its readiness to assist Ukraine in building the necessary army.

Ukrainian officials could certainly seek commitments from Western countries to impose sanctions on Russia should it attack again. But a robust Ukrainian military, equipped with modern defensive weapons, would offer Kyiv the strongest guarantee that it could defend itself against a future Russian armed attack and, ideally, deter the Kremlin from ever again considering such an invasion.

Steven Pifer is a William J. Perry Fellow at Stanford’s Center for International Security and Cooperation and a former U.S. ambassador to Ukraine.