Refugees fleeing the Russian invasion make their way through western Ukraine to the Krakovets border crossing with Poland on March 9, 2022.

Refugees fleeing the Russian invasion make their way through western Ukraine to the Krakovets border crossing with Poland on March 9, 2022. Dan Kitwood/Getty Images

Establish a Zone of Peace in Western Ukraine

Sending foreign troops to defend so-far-uncontested territory is the only way to preserve a free Ukraine and prevent Putin’s next attack.

No one knows how far Russia's Vladimir Putin will push his brutal attack on Ukraine. Western commentators initially assumed that Putin would allow the existence of a Ukrainian state, minus the Donbas, under a puppet government once Kyiv, Kharkiv, and Mariupol are conquered; Ukrainian President Volodymyr Zelenskyy executed; and a wide coastal corridor between Crimea and Donbas region established. But after a March 3 call with Putin, French President Emmanuel Macron warned that the “the worst is yet to come” and that Putin’s objective is to take all of Ukraine and obliterate the nation. Just days later, Putin threatened to end Ukrainian statehood unless resistance stops.

Thus far, the primary response of the world has been sanctions. It is a significant effort and has demonstrated the unity of democratic states. However, sanctions only work against governments that are actually concerned about the long-term economic well-being of their people. It is quite evident that Putin will sacrifice such well-being for immediate objectives and the prestige of military power. Efforts to provide Ukraine with additional weapons are tactically important, but Ukrainian forces are just too small to sustain a conventional war against Russia. 

If there is to be any future for the Ukrainian nation, the West must act immediately to establish a peacekeeping and humanitarian relief zone in unoccupied western Ukraine. This “Zone of Peace” would be maintained by fully armed troops, either from NATO, the EU’s “Defence Forces of the European Union,” or—although a difficult aspiration—a coalition of non-European states ostensibly under United Nations General Assembly authority. The zone would be intended to both protect civilians and preserve a semblance of independence for the Ukrainian people. If requested by President Zelenskyy, such an action would be in full accordance with international law. As Zelenskyy has repeatedly stated—most recently in the wake of Russian shelling of a nuclear power plant—“only urgent action by Europe can stop the Russian troops.” 

Instead of confronting Russian forces in their current operations, these peacekeepers—fully equipped for combat—could establish defensive positions in those areas of Ukraine that Putin’s soldiers have not yet reached, including the oblasts of Lviv, Volyn, Zakarpattia, Rivne, Ternopil, Khmeinytski, Ivano-Frankivsk, Chernivitsi, Zhytornyr, Vinnytsia, and the northern and coastal sections of Odessa not yet contested. Obviously, the central city would be Lviv, to which most embassies and many refugees have already moved and which The Economist has already dubbed “the place of plan Bs.” The goal would be to create a protective barrier around what can be saved of a sovereign Ukraine that will survive in the near-inevitable event of the fall of Kyiv and eastern regions. And, yes, it would include a no-fly zone, but exclusively above the protected area. 

Once established in position, these peacekeepers would take no offensive action against Russian forces operating in the rest of Ukraine, but remain fully prepared to defend themselves and the territory they protect. These would not be the lightly armed “peacekeepers” that have proven largely ineffective in past UN operations. These forces would avoid initiating hostilities, but act as a powerful deterrent to additional ones. It will henceforth be Putin’s choice whether he wants to fight Europe, and perhaps the world, a war he knows Russia cannot win. Such a war would be likely to topple him, the outcome he most fears. 

Escalate to de-escalate

Ironically, this would apply a strategic logic that has been attributed—perhaps somewhat inaccurately—to current Russian military strategy: escalate to de-escalate, or escalation control. In this case, the escalation is the presence of Western troops in unconquered Ukraine. The de-escalation is that it will force Putin to confine his action to what he claims to be doing: “liberating” the Donbas and replacing the Ukrainian regime, which without direct Western action is impossible to stop. Presence of the peacekeeping force would establish a deterrent and firm redline that would allow—indeed, entice—Putin to declare victory and back away. In short, the threat of further war is what would quell the current war, which is an effective definition of deterrence. 

The actual concept is derived from interpretation of Russian writings on the use of nuclear weapons that implied that escalating the use of force—using small tactical nuclear weapons against an opposing force—might cause the opponent to forgo any further effort on bringing even greater power (a greater conventional force or even strategic nuclear weapons) into the conflict. Escalating to deescalate has been described as “escalating a conflict to a level of a conflict to a level of violence that causes the adversary to cease military operations [which] would be just one example of how Russia might seek to control escalation of a conflict.” As applies to U.S. nuclear forces, the concept has been rejected in Congressional testimony by U.S. joint military leadership. But outside of the nuclear posture, it does correspond well to the elements of conventional “deterrence by denial.” A strong, well-equipped and well-trained force (such as NATO contingents) set in protected positions but capable of maneuver is a deterrent that iterative responses cannot equal.

Evidence of inept operations in Ukraine may not reflect the true competence of the overall Russian armed forces. But it does suggest that pushing against a combat-ready peacekeeping force ultimately backed by NATO is not a challenge Russian military commanders would want to chance. 

What forces are needed?

Rapid reaction force-type light infantry would form the leading edge or boundary of the Zone of Peace, with armor, artillery and combined arms forces kept at a distance. These heavier forces would not be a single centralized reserve; they would be established throughout the zone, but in positions that do not signal a forward offensive. 

Preferably the light infantry barrier would not include any U.S. troops (to avoid playing into the Putin narrative), but would be comprised of European NATO and/or EU nations, or other willing UN members. There are, in fact, a number of nations who might be willing to provide troops if subsidized and backed by the West. The heavier forces would be built around at least three U.S. Army or U.S. Marine Corps divisions (or equivalents). The clear message: we do not intend to advance to create a general war, but we will not retreat. 

Ukrainian forces would not be a part of the peacekeeping/defensive force, but would be permitted to retreat to cantonments within the zone if they agree to cease operations within the contested areas of Ukraine. Attacks by Ukrainian forces from the Zone of Peace would not be permitted.

Movement of the peace-zone forces would be primarily by ground transport through Poland, Slovakia, Hungary, or Romania, and preferably all of these. Helicopter insertion is a possibility, but would best be minimized until the Zone of Peace is initially established and declared. If Odessa remains unoccupied, forces could be moved by ship or watercraft from Romania, Bulgaria or Turkey.   

Covering airpower would be based outside Ukraine, but could be present above the Zone of Peace as needed once the zone is established. The purpose is to protect the zone, not to recover what is lost. Fighters and close air support aircraft would predominate; unless a general war ensued, there would be no role for long-range bombers. 

Would such an operational posture be in accordance with U.S. Army, U.S. Air Force or joint doctrine? Not at all. U.S. combat operations are based on taking the fight to the enemy in territory the enemy controls. However, the unique and tragic circumstances of the situation require a creative approach that transcends doctrine. The goal is to preserve Ukrainian sovereignty in those areas not yet under Russian occupation, in order to provide humanitarian support for the Ukrainian people and keep an independent future for them alive while avoiding a general war with Russia. This is not achievable through mere sanctions. Neither can it be achieved through cyber war.   

Would it cause a nuclear war?

The obvious fear that makes Western nations wary of open intervention in an unjust conflict that could shred the presumed “liberal world order” is the fear of nuclear war. My contention is that this possibility can be managed by restraining the military effort to preserving the territory still under control of Ukraine government. As terrifying as the prospects of a nuclear exchange may be, deterrence should hold, even in Putin’s mind, if conflict on Russian territory or with Russian forces is avoided. 

Offensive operations that push the Russians out of Ukraine altogether would be the ideal outcome for the conflict, but that again plays to Putin’s narrative and could provoke an uncertain response. Such operations would remain the purview of Ukrainian military (and civil) forces. Defense of unoccupied Ukraine is altogether different. 

To argue that an established Zone of Peace would prompt the use of Russian nuclear weapons is to argue that a nuclear war is inevitable during the lifetime of Vladimir Putin. If that is true, then the world has little option but to surrender to his increasing demands.

The invasion of Ukraine is not simply about the future of Ukraine. It is about the global future in which Ukraine invasions become the norm. Perhaps a small amount of risk concerning a nuclear outcome is required. We’ve been there before in the Cold War and deterrence prevailed. Putin is a creature of the Cold War.

Does a static defense make sense? What will be the outcome?

Operational planners will argue that the static defense inherent in such a Zone of Peace operation does not make sound military sense. And, from the perspective of an all-out conflict, they are correct. Such a course of action limits the operational maneuver that is seen as the key to modern warfare and perhaps the most desirable attribute for any military force. It would allow for tactical maneuver, but forgo the advantage of multi-axis attack and operational deception. 

However, the objectives—again—do not include the destruction of the enemy’s forces, but the maintenance of the current status quo in specific territory. It is to check the enemy’s king, not kill his pawns. Comparisons to failed defensive efforts in history may be inevitable, but what should be remembered is that strong defenses only fail when the enemy has substantially superior forces, or when the defenses are flanked; the Maginot line being the classical example. Russian forces are inferior to a combined NATO and are not demonstrating their potential capabilities well in Ukraine. The potential for a breakthrough or a flanking of a well-prepared Zone of Peace defense is relatively modest.

What effect on the narrative?

An additional concern would be the potential effect on the “narrative” concerning which side is the aggressor. Could Putin claim that the establishment of the peacekeeping force constitutes an “attack” by NATO? 

The Russian president-for-life has styled sanctions as “akin to an act of war” and threatened that Russia will be at war with any nation that provides or hosts Ukrainian aircraft. Undoubtedly, he would try to spin any peacekeeping forces as an attack.

However, he has not been successful at seizing the narrative. Numerous nations have imposed sanctions and provided Ukraine with sophisticated anti-tank and anti-aircraft weapons and Putin has been powerless to stop these actions and has not declared war against them. Nor has he been able to spin these actions to support his arguments. The key for Western governments in continuing to dominate the narrative will be to use the term “peacekeepers” in every statement—perhaps as every second word.

Immediately securing the Ukrainian nuclear power plants at Rivne and Khmeinytski—an action the peacekeeping force should take in any event—would also maintain Western dominance of the narrative given the concerns expressed throughout Europe over Russian strikes on the nuclear power plants in the east. A clear justification for the peacekeeping force is to prevent a Chernobyl-type disaster caused by Russian attacks on the nuclear plants.            

Let’s not repeat history

The possibility of establishing a protected Zone of Peace is already being discussed quietly in Europe. Portuguese Prime Minister Antonio Costa has hinted that his government was willing to put its (admittedly small) forces on the ground in Ukraine. This discussion has not yet penetrated the awareness of Americans and there is no indication that President Biden’s administration is considering the option. But it should be openly and widely discussed here and considered now while it can still be implemented.

Some experts have maintained that Putin’s objectives are limited. That is, as often said, hope not strategy. Some maintain there are no historical parallels since the “world is so different now” because of technology or availability of information (soft power), but that could be a quote from 1939. Russian sources claim that Putin sees himself as the new Stalin. This has long been suggested. However, the parallels to 1939 are even greater; Donbas is very much Putin’s Sudetenland, Hitler’s “last demand of Europe.” Ukraine is poised to become Putin’s Czechoslovakia: the rest of the country Hitler annexed while an indifferent world did not react. Fortunately, this time the world has reacted—but it has not yet reacted enough.

Avoiding the mistakes of the past is more than a practical issue; it is also a moral issue.  

The protection of what remains of Ukraine is a moral obligation. It would save many Ukrainian lives (and perhaps those of Russian conscripts). The decision of the Ukrainian people to move towards democratic governance and integration into European society was inspired and encouraged by western Europe and the United States. To forgo taking action beyond imposing economic sanctions is a betrayal of trust and would be a severe setback to democracy everywhere. Why should any nation turn to democracy if the result will be invasion, death, and subjugation by a more powerful authoritarian state? 

The real “Thucydides trap” is not the fear of rising rival powers, but to allow the future international system to be defined by the principle that the ancient Athenians violently taught the Melians: “the strong do what they will, the weak suffer what they must.” Melos was not merely captured; its men were massacred and women were enslaved. Melos was repopulated by Russians—correction—I mean, Athenian colonists. 

That is the future that Vladimir Putin (and Xi Jinping) want to bring about. Subjugating Ukraine would the most significant step yet in making that future a reality. To prevent it—to preserve a world constantly striving toward law and justice—requires the preservation of the so-far-uncontested territory of Ukraine by establishing and enforcing a Zone of Peace.

Yes, the most likely result would be an East Ukraine (Russian-controlled) and a West Ukraine (independent and sovereign). But that would preserve the hope that—like East and West Germany—Ukraine will be united again in a future beyond Putin. Sanctions won’t do it. Cyber won’t do it. Offensive warfare brings great risk. An enforced Zone of Peace is the option worth taking.

Sam J. Tangredi holds the Leidos Chair of Future Warfare Studies at the U.S. Naval War College. He is the author, most recently, of Anti-Access Warfare: Countering A2/AD Strategies. The views expressed are completely his own and do not necessarily reflect the official views of the U.S. Naval War College, U.S. Department of Defense, or any other agency of the U.S. government.