Credible Security Guarantees for Ukraine

On May 9, President Vladimir Putin claimed that Russia’s war may be “coming to an end.” Although this is uncertain, the West should delay no longer in defining how it might help Ukraine protect itself after a ceasefire. Ukraine’s potent military will be its best defense, but the West can do more to help it foil further Russian aggression. 

A security guarantee is a mutual defense obligation. For example, the NATO Treaty’s Article 5 states that “an armed attack against one NATO member shall be considered an attack against them all.” All allies guarantee each other’s security.  In the U.S., such a guarantee requires a two-thirds vote by the Senate. 

In the Cold War, NATO members made guarantees more credible by training and exercising their forces with those of other allies, and by basing forces forward. The U.S. put forces in several frontline states, such as Italy, Turkey, and West Germany. 

Ukraine’s security environment bears a resemblance to South Korea’s. Both face hostile, well-armed, revanchist neighbors. U.S.-led United Nations Forces in South Korea help it deter and defend against aggression. Combat-capable Western forces in Ukraine could do likewise. 

Western guarantees should meet high standards. 

Surprise attacks are a special concern. Recovering territory is more difficult than protecting it. Some have spoken of a “reassurance force” at “fallback locations” in Ukraine. This might preclude timely support to Ukrainian defenses, or cause Russia to think that in a crisis Western troops might leave Ukraine, as did NATO trainers in early 2022. 

Poorly designed Western forces in Ukraine could stir doubts. Those aimed at funneling military aid might lack the strength to help Ukraine fight.  

Some in the West say that putting forces in Ukraine would require Russia’s assent. Obtaining it is a fantasy. UN Forces have helped South Korea sustain an armistice for seven decades without the North’s assent. 

With the West unwilling now to insert forces, how could Kyiv count on them to surge into Ukraine in a crisis? This is why having Western forces in Ukraine after a ceasefire is so important. They should meaningfully augment Ukraine’s 900,000-strong combat-tested army. Western contributors ought to make clear to Moscow that their forces will fight if attacked. 

A combined forces command, as in South Korea, may be impractical. NATO members might hesitate to put their units under non-NATO command. And until joining NATO, Ukraine could resist placing its forces under Western command. A good option might be separate Western forces closely linked to Ukraine’s.   

Since Ukraine is advanced in countering drones, Western air defense units might focus on cruise and ballistic missiles. Some defenses could be based in Ukraine and others in neighboring NATO states, perhaps flying combat air patrols and counter-air surges. 

An ceasefire accord ought not to allow Russian warships to return to Crimean ports. They could again threaten southern Ukraine and Black Sea commerce. NATO littoral allies - Bulgaria, Romania, and Turkey - could guard Black Sea shipping lanes and protect against sea-based Russian attacks without being limited by the Montreux Convention. 

A ceasefire might allow Ukraine to draw down some of its forces and focus more on recovery without leaving itself vulnerable to surprise attack. The defensive fortress belt in eastern Ukraine might be expanded and augmented with emerging technologies for multi-spectrum sensing and unmanned aerial patrols. 

Deploying Western forces in Ukraine could sharpen tensions with Moscow. But the Cold War showed that standing up to bullying - as the West did in 1948-49 with the Berlin airlift - earns Moscow’s respect and might induce more caution. 

The priority now is for the West to help Ukraine achieve a stable ceasefire. This should mean increased support for its courageous and innovative fighting force. If a ceasefire emerges, the West ought not to skimp on helping Ukraine to enforce it. 

Russia’s record of violating nearly every pledge and treaty underlines the need to help Ukraine prevail on the battlefield. Absent this and a Western force presence, Ukraine could be left with only words, not real security guarantees. 

William Courtney was a career foreign service officer and ambassador to Kazakhstan, Georgia, and the U.S.-Soviet Commission to implement the Threshold Test Ban Treaty. Philip Wasielewski is a retired Marine Corps Reserve colonel who also had a 31-year career in the CIA’s Directorate of Operations. He served from 2014 to 2017 on the National Security Council staff.