Clausewitz, Theory, and Ending the Ukraine War

Introduction

Perhaps the greatest weakness in strategic thinking and the relative literature is planning how to end a war, particularly before launching it. In some respects, this nearly universal historical failure is understandable. The overwhelming pressure of fighting a war often inhibits nations from seriously considering how to end it.[i] Clausewitz noted the importance of this issue, especially when a war is becoming increasingly bloody. The last sentence here is key:

Theory, therefore, demands that at the outset of a war its character and scope should be determined on the basis of the political probabilities. The closer these political probabilities drive war toward the absolute, the more the belligerent states are involved and drawn in to its vortex, the clearer appear the connections between its separate actions, and the more imperative the need not to take the first step without considering the last.[ii]

But what would Clausewitz, and some additional theories, say about this most complicated of tasks: ending a war, particularly the war in Ukraine?

The Problem: Planning A War’s End

Sometimes war is thrust upon you with no chance to plan for its termination before it begins—which was Ukraine’s case when Russia escalated its war in 2022—or you are simply too weak to see a way out—a description of Ukraine’s situation vis-à-vis Russia from 2014-2022. This is especially true for smaller powers forced to defend themselves from larger ones, which also describes the Russia-Ukraine War. In such cases, tough resistance can provide time for the situation to change. Such was Finland’s case in the face of the 1939 Soviet invasion. Hard fighting preserved Finland’s independence.[iii] The fierceness of Ukraine’s resistance since 2022 bought Kyiv time to gather strength internally and abroad, wore down the Russian army, and provided room for a 2023 counteroffensive.

But this doesn’t mean one achieves the peace they want. In 1940, the Finns journeyed to Moscow hoping to negotiate, but received no choice but to sign—unchanged—a treaty drafted by the Soviets.[iv] The 2022 Ukrainian counteroffensive liberated much Ukrainian territory but didn’t inflict decisive defeat upon Russia’s military or deliver Kyiv’s aims.

How To End A War

Those facing the perplexing task of ending any war must keep in the forefront of their minds these three critical questions:

1. What is being sought politically?
2. How far must or should one go militarily to achieve this?
3. Who will maintain the peace settlement, and how?[v]

The number of factors in play around each of these ideas is simply overwhelming, this complexity demands systematic analysis. Moreover, these issues are inextricably intertwined. This is not a checklist. The forces related to all three work simultaneously.

1. What Is Being Sought Politically?

We start here because this is what the war is about, and it is an objective basis for analysis. Clausewitz shows that all wars are fought either for regime change (what we call an unlimited aim), or something less (a limited aim). He notes: “The ultimate object is the preservation of one’s own state and the defeat of the enemy’s; again in brief, the intended peace treaty, which will resolve the conflict and result in a common settlement.”[vi]

The Political Aim and The Value of the Object

Clausewitz insists upon understanding the political aim or aims of the combatants and the value each places upon their respective objects, or aims. He wrote: “Since war is not an act of senseless passion but is controlled by its political object, the value of the object must determine the sacrifices to be made for it in magnitude and also in duration. Once the expenditure of the effort exceeds the value of the political object, the object must be renounced and peace must follow.”[vii]

Putin’s words and deeds make his aims clear: the destruction of an independent Ukraine and its assimilation into Russia. Russia’s military setbacks haven’t diminished Putin’s unlimited war aims because he places the highest value on conquering Ukraine, which he views as essential to restoring Russia and preserving his regime.[viii] In 2005, Putin decried the Soviet Union’s breakup as “the greatest geopolitical catastrophe of the century.”[ix] In seeking to reverse this, Putin has long focused on discrediting Ukrainian sovereignty and laying claim to its territory. He told US President George W. Bush in 2008: “Ukraine is not a real country” and pressed Russian claims to Ukrainian territory in a 2021 historical essay and again in a speech on the eve of his 2022 full-scale invasion.[x]

Putin’s February 2024 comments that the war “is our fate; it is a matter of life and death,” reflects his belief in the historical necessity of Russia’s possession of Ukraine for it to survive as a great power.[xi] It may also demonstrate his paranoia about losing power. Putin publicly claimed in February 2024 that the West is “bent on destroying Russia.”[xii] This view is buttressed by his conviction that Washington backed Chechen rebels, engineered “Color Revolutions” on Russia’s periphery, and sponsored a 2014 far-right “coup” deposing his Ukrainian proxy Viktor Yanukovich.[xiii] Likewise, Yevgeny Prigozhin’s short-lived march on Moscow in the summer 2023 and the failure of his underlings to speak out in his defense presented Putin with a potent reminder of the fragility of his regime, should Russian forces fail in Ukraine.[xiv]

Ukraine’s aims are also clear. Kyiv wants to maintain its independence and territorial integrity. The first requires defending the state against Russian attacks, and the second offensive action to recover lost territory. The first demands steady and consistent military defense. The second will require successful and sustained offensives. Beyond the military challenges, which are discussed below, are the political difficulties Ukraine could face from its supporting partners. If Ukraine succeeds in recovering the territory it held in January 2022 (not 2014), it will encounter immense pressure from the US and Europe to seek peace and accept the pre-2022 de facto border with Russia. Zelensky consistently rejects any territorial concessions, but his partners, who supply much of Ukraine’s arms and munitions, will disagree.[xv]

Western observers, however, underestimate the depth of Zelensky’s resistance to significant territorial concessions. [xvi] Doing so—considering Russia’s brutal war and rapid assimilation of occupied territories—would leave millions of Ukrainians at Moscow’s mercy.[xvii] Putin’s abrogating ceasefire agreements with Chechnya, Georgia, and Ukraine would give any Ukrainian leader pause about striking this Faustian bargain. [xviii] As Clausewitz observed, time accrues to the defender, suggesting that Kyiv’s prospects for recovering lost territories would soon fade if it backed such a deal.[xix] Conversely, an emboldened Putin would find himself in a strong position to attack a rump Ukraine from its former territories after exploiting the ceasefire to refit his forces.

2. How Far Must Or Should One Go Militarily?

When trying to deduce the proper use of military power for ending a war one must—as always—keep the political aim or aims being sought firmly in mind. As Clausewitz tells us, this is the basis for analysis and all else flows from here.[xx] There are, of course, many routes to victory, and Clausewitz draws a useful list of options for using military power to end a war:

1. destruction of the enemy’s forces
2. the conquest of his territory
3. a temporary occupation or invasion
4. projects with an immediate political purpose
5. passively awaiting the enemy’s attacks.

“Any one of these,” he insists, “may be used to overcome the enemy’s will: the choice depends on circumstances.” Moreover, the personalities of leaders and their personal relations add infinite further possibilities for achieving the political aim.[xxi]

a. First, the “Destruction of the Enemy’s Forces”

Clausewitz’s first option is “the destruction of the enemy’s forces.” Some so-called “limited war” literature argues against this.[xxii] But that is a self-imposed constraint ignoring the realities of warfare, history, and human nature. Recent generations of Western political and military leaders often fail to realize destroying the enemy forces is often the prerequisite for victory and achieving the political aim.

Though Ukraine seeks a limited aim (something less than regime change), and Russia an unlimited aim (regime change), both have tried to achieve victory by destroying the enemy’s forces, particularly Russia, which initially gambled on annihilating Ukraine’s army, failed miserably, and wrecked its own.[xxiii] The Ukrainians seem to have recently adopted a defensive attrition strategy in the hopes of wearing down Russia’s will or military forces, perhaps both. Currently, each lacks the power to fatally injure the enemy’s forces. This could change if Russia mobilizes further or Western support for Ukraine lessens or ends, or if Ukraine receives aircraft and ground defenses enabling Kyiv to gain control of the air.

Clausewitz writes that when using military force, it may not be possible to completely overthrow the enemy. In discussing his “culminating point” he warns one can go too far: “Thus the superiority one has or gains in war is only the means and not the end; it must be risked for the sake of the end. But one must know the point to which it can be carried in order not to overshoot the target; otherwise instead of gaining new advantages, one will disgrace oneself.” Clausewitz, when discussing “the culminating point of victory,” warns: “Even if one tries to destroy the enemy completely, one must accept the fact that every step gained may weaken one’s superiority.”[xxiv] Moreover, going too far “would not merely be a useless effort which could not add to success. It would in fact be a damaging one, which would lead to a reaction; and experience goes to show that such reactions have completely disproportionate effects.”[xxv]

There are few better historical examples of what Clausewitz wrote above than military events in Ukraine in 2022-2023. Russia invaded, underestimating its opponent and its own ability to execute its plans. It lacked the strength to achieve its operational, strategic, and political aims, became overextended militarily (Russia passed the culminating point), had to surrender some gains, and fell victim to a Ukrainian counterattack forcing Russia to cede much of its gains.

Drastically increasing forces can affect the enemy politically by giving opportunities to enemy leaders who want peace or convince the enemy leaders to make peace. Gradually increasing forces or violence doesn’t usually produce a shift toward peace. These are more easily absorbed or countered. However, a minor increase in military force might—indirectly—produce change over time via battlefield victory or produce a military stalemate that convinces the enemy to make peace.[xxvi]

And it is here where both Ukraine, Russia, and the Western nations supporting Ukraine have erred. At the war’s outbreak, Zelensky declared a general mobilization, banning all Ukrainian men between 18 and 60 from leaving the country. But the draft age remained at 27 until April 3, 2024. Ukraine’s parliament passed legislation lowering eligibility to 25 in May 2023, but Zelensky delayed its signing in hopes it wouldn’t be needed.[xxvii] Ukraine should have immediately lowered its draft age to 18 and built a larger army. This would have been difficult but possessing more forces for its 2023 offensive would have meant a better chance of dealing the Russian army a decisive blow. Russia failed similarly by initially committing insufficient forces and sporadically mobilizing since. Ukraine’s Western supporters failed in sending arms and equipment quickly enough when it became clear Ukraine wouldn’t immediately succumb.

b. Second, “the Conquest of His Territory”

Clausewitz advised:

Even when we cannot hope to defeat the enemy totally, a direct and positive aim still is possible: the occupation of part of his territory. The point of such a conquest is to reduce his national resources. We thus reduce his fighting strength and increase our own. As a result we fight the war partly at his expense. At the peace negotiations, moreover, we will have a concrete asset in hand, which we can either keep or trade for other advantages.[xxviii]

One may not be able to immediately make newly captured territory reduce the costs of waging the war, but it certainly provides a bargaining chip for peace negotiations.

Russia has seized substantial amounts of Ukrainian territory, but Putin isn’t interested in using any as bargaining chips, though he has tapped it for resources and military manpower. For Putin, controlling territory is the war’s point. The Ukrainians feel similarly and are unwilling to allow Russia to keep any seized land. Until one or both sides are willing to bend here, or the army or government of the other collapses, there is little hope for peace.

c. Third, “a Temporary Occupation or Invasion”

The US temporarily occupied Mexico City in 1848 to force an end to the war.[xxix] But currently, barring some strange events, this seems not applicable to the Russia-Ukraine War. Ukraine could conceivably take a piece of Russia, temporarily emboldening Kyiv and embarrassing Putin. Russia could score a dramatic coup-de-main against Ukraine, but this would further convince Putin of the correctness of his actions.

d. Fourth, “Projects with an Immediate Political Purpose”

Action against Putin by internal groups à la Prigozhin would be the ultimate “project with an immediate political purpose.” Putin’s death or the fall of his regime could end Russian expansionism. But it also might not. This would depend upon who and what followed. Zelensky could also die or be killed, but in democratic states fighting existential wars, the change of political leader doesn’t usually produce an alteration of the political aim as the formulation of aims is not generally determined by a single individual. When US President Franklin Roosevelt died in 1945 and was replaced by Harry Truman, the US aim of “Unconditional Surrender” of the Axis powers remained.

e. Fifth, “Passively Awaiting the Enemy’s Attacks”

This means fighting a defensive war to hold one’s possessions. At the end of the Russo–Japanese War (1904-1905), both sides awaited one another’s attacks. Japan had exhausted its army, and its military leaders considered further advances disastrous. The Russians were pouring in reinforcements and many Russian leaders still wanted to fight. But Russia also suffered from what became the failed 1905 Revolution and needed forces for internal security.[xxx] Tough negotiations for peace followed.

Awaiting the enemy’s attacks is an option for both Moscow and Kyiv, but these are routes for a long, bloody, war where neither is likely to achieve its current political aims. Ukraine cannot clear all its territory by only fighting defensively. Russia can’t conquer Ukraine without offensive action.

3. Who Will Maintain The Peace Settlement, And How?

Clausewitz cautions: “Lastly, even the ultimate outcome of war is not always to be regarded as final. The defeated state often considers the outcome merely as a transitory evil, for which a remedy may still be found in political conditions at some later date.”[xxxi] The 1954 Geneva Accords and the 1961 agreement to neutralize Laos provide examples. The North Vietnamese Communists signed but never intended to abide by the terms.[xxxii] Some agreements ending wars are temporary expedients.

Also, one must consider the differences in ending wars fought for limited and unlimited aims. Some argue it’s easier to enforce terms such as disarmament by overthrowing the regime and heavily occupying the defeated, thus creating a more stable post-war environment.[xxxiii] Sir Basil Liddell Hart argued that a negotiated peace to which the combatants have not been forced to conform because their power has been destroyed and in which they freely participate (he sees something like the eighteenth-century model) is easier to maintain, and the signatories more likely to keep the terms because they have agreed to them. If terms are forced upon them, they are more likely to feel no obligation to maintain them.[xxxiv] Both of these observations are correct. Every peacemaking situation is as unique as every war making one. The variables and their weights are distinctive to each event. Successful peacemaking may require as much creativity as successful warfighting.

Making A Peace Work

Deciding when to end the fighting can be difficult, some argue it can end too soon. Theorist Edward Luttwak says “an unpleasant truth often overlooked is that although war is a great evil, it does have a great virtue: it can resolve political conflicts and lead to peace. This can happen when all belligerents become exhausted or when one wins decisively. Either way the key is that fighting must continue until a resolution is reached.” He adds that in our present era conflicts among less powerful states are often stopped “before they could burn themselves out and establish the preconditions for lasting settlement.”[xxxv] The problem, of course, is what this may mean. It is entirely possible that Western support, Ukrainian will, Russian manpower, and the high value Putin places upon achieving his political aims, will ensure this war continues for years. Neither Russia nor Ukraine have produced serious signs of bending on their aims.

One can face a situation where it is impossible to secure a peace even after winning militarily. In his examination of the problems terminating a future Russia-NATO war in the Baltic States, one investigating a scenario where NATO drives out the Russians, Lukas Milevski shows NATO’s inability to convince nuclear-armed Russia to make peace. “Russia would be thwarted,” he notes, “but not defeated and there would be no politically acceptable way of using military force to coerce Russia into acquiescing to defeat.”[xxxvi] Does this also describe Russia’s current war?

There are two factors critical to making a peace work: 1) a formal treaty; and 2) clear and enforceable terms. It would be foolish, though, to assume these are silver bullets and the only things to consider. This is the ideal, but peacemaking is more difficult when a state fights for a limited political aim (Ukraine’s case), because here, usually, one hasn’t completely disarmed the opponent; nor is the opponent necessarily prostrate and forced to accept whatever peace is dictated, something unlikely in Russia’s case.

A Formal Treaty: Problems and Promises

Clausewitz writes: “The ultimate object is the preservation of one’s own state and the defeat of the enemy’s; again in brief, the intended peace treaty, which will resolve the conflict and result in a common settlement.”[xxxvii] But getting here is exceptionally hard. One key to securing a lasting peace is a formal settlement. Done properly, this removes ambiguity. One strength of the Second World War’s settlement was the Allied insistence on formal acts of surrender from Italy, Germany, and Japan, agreements arranged by official representatives of both sides.

Ideally, one of the things a peace agreement should do is resolve the problems producing the war. Some consider this the best route to a lasting peace, but such treaties are rare since the end of the Second World War.[xxxviii] Even the victorious parties didn’t agree what caused the First World War. To France, it was German aggression; to Britain, the collapse of Europe’s balance of power; to the US, it was secret treaties. This multiplied the peacemaking problems.[xxxix] Coalition partners should sort out their differences early.

Machiavelli wrote: “If one wants to find out if a peace settlement is stable or secure, one has among other things to figure out who is dissatisfied with that settlement, and what can grow out of such dissatisfaction.”[xl] Historian Michael Howard said, “a war, fought for whatever reason, that does not aim at a solution which takes into account the fears, the interests and, not least, the honour of the defeated peoples is unlikely to decide anything for very long.”[xli] Ending wars with several powers usually means concluding several treaties.

An armistice or ceasefire that stops the fighting isn’t the same as a settlement concluding the war. Unless the agreement to stop the fighting has a time limit, an armistice can become a de facto settlement. Such agreements can make it easy to restart hostilities and almost always lack official political acceptance of their permanence, even if continuing for decades.[xlii] The 1953 Korean War “settlement” is an armistice not a peace agreement. One must remember this distinction. An armistice isn’t preferred but is sometimes what’s possible.

Western observers advocating negotiations between Russia and Ukraine generally underestimate the value each places on their respective political aims. This is particularly true regarding assessments of Putin. His deep-seated desire to conquer and assimilate Ukraine, in turn, makes it harder for Kyiv to abandon territories to Russia for the undoubtedly false hope of surviving as a rump state with a revanchist and emboldened Russian neighbor. As the conflict grinds into its third year, this value continues to rise for the leaders on both sides, as do the stakes of defeat.

Enforcing the Terms

One analyst says of treaties: “If either belligerent expected that the other would not honor the agreement, it is improbable that they would accept the agreement in the first place.”[xliii] This provides room for hope. However enforcing treaty terms can be more difficult than securing them. One challenge is the defeated not accepting the agreement’s articles. When Prussia made peace with Napoleon in 1807, it ignored the military restrictions placed upon it and mounted clandestine efforts to improve its military status in which Clausewitz participated.[xliv] Germany cheated extensively on the 1919 Versailles Treaty.

The time for enforcing disarmament clauses and other terms is limited because states start to wriggle out of them. Moreover, the victors and the members of the international community lose interest, become distracted by more important matters, and hinder enforcement because they begin to regard the victor poorly. The victor’s insistence upon enforcement can see it deemed a threat to peace. This strange dichotomy creates an argument for the victor making a quick peace and the defeated pursuing delay, depending upon their situations. There is also the opposite enforcement problem: those signing up for the job refuse to bear the burden. Only four of the twenty-seven signatories of the 1919 Versailles agreements did their part as enforcers during the 1923 Ruhr occupation.[xlv]

Other problems abound. Geography can affect enforcement because of the proximity of the defeated to the victors. After the First World War, distance and the Atlantic Ocean allowed the US to ignore a revisionist and revanchist Germany; France could not.[xlvi] Disputes over postwar territorial control also weaken settlements. One scholar insists “Territory is the only variable that significantly affects the risk of recurrent conflict.”[xlvii] This point is particularly applicable to the Ukraine War. Ukraine is vastly more interested in maintaining its territorial integrity than the US and Western Europe. Kyiv shows no signs of bending here.

Numerous ways exist to enforce treaty terms, but most of what statesmen have done to resolve issues of both war and peace have made the world less stable and produced war, not peace.[xlviii] Structures need to be built to protect everyone’s rights.[xlix] This is difficult. Monitoring with external groups is common but deciding upon monitors is tough because of suspicions. Occupation or peacekeeping forces are options but come with their own problems. Reconciliation is the ideal.[l] The history and the emotions behind the problem make achieving this difficult. Securing this between Ukraine and Russia is a monumental task.

Victory in the war does not always mean peace, which could be Ukraine’s fate when one considers the nature of Putin’s regime. Democratic Israel’s victories over its generally authoritarian neighbors kept the state alive but didn’t bring peace. Some in the democratic West resent its success and survival.[li]

One thing sometimes necessary for maintaining the peace is rebuilding the other state. Historically, this has proven difficult. One author noted that in cases since 1898 where the mission was completed or ended, the US and UN succeeded only 48 percent of the time. Analysts and practitioners neither understand nor agree upon how to produce success. The literature suggests different approaches: liberalization first, or building institutions first, or providing security first. Some argue for finding the right sequence; others believe sequencing a myth because every situation is different.[lii] Since the Second World War, achieving security and stability in a nation has only been possible in states capable of doing it themselves.[liii]

Demilitarized zones can help guarantee peace, especially if big enough to keep forces separated, such as the ones established in the Golan Heights between Israel and Syria, and between North and South Korea.[liv] Some believe “mechanisms such as demilitarized zones, monitoring, and arms-control limitations are not merely effective in mitigating security fears arising from commitment problems; because such mechanisms increase the costs of returning to war, they generally increase the contact zone and thereby enhance the robustness of the settlement.”[lv]

There can be problems securing the peace if one doesn’t make clear to a defeated state’s population that its leaders have lost the war. This can have unfortunate consequences, especially if the defeated state is revanchist. After the First World War, the victorious Allies didn’t make this clear.[lvi] But one may need to ensure the defeated opponent isn’t humiliated; this can cause bitterness and make securing the peace more difficult. After the fall of Napoleon in 1815, Clausewitz was part of the Prussian occupation force in France. He participated in Prussian forced requisitions of goods and material and criticized punitive actions. He believed the British more intelligent in their peacemaking because they behaved with generosity and thought the Prussians bad winners.[lvii]

There is little chance of much of this being relevant to the Ukraine-Russia War while Putin holds power. But as a thought experiment, assume a negotiated settlement preserving Ukraine’s independence in some form while Putin still rules. Who would enforce the terms? Western powers would undoubtedly insist upon a UN peacekeeping force on the common border, one Russia would refuse, especially if it included NATO forces. Both Russia and Ukraine would demand the other disarm in some respects. This would be easily monitored in Ukraine and cheated upon incessantly in Russia. Subsequent widespread Russian subversion of Ukrainian elections, media, business, and government would ensue, despite promises to the contrary. Any reparations Russia agreed to would be ignored; only a handful of the kidnapped Ukrainian children and adults would be returned, despite Moscow’s promises. One quickly sees the problems. With Putin in charge, any peace between Russia and Ukraine will be nearly impossible to enforce. More importantly, in Moscow’s eyes, it will be very temporary, a mere breathing spell. And the next time, Russia would be better prepared.

Conclusion

A quick end to the Russia-Ukraine War is unlikely. The challenges of ending wars, particularly if neither opponent is prostrate, are particularly deep in the current situation. An unpredictable event or series of events could occur, producing a sudden willingness to make peace in one or both combatants, but such is unlikely. We must, as Clausewitz tells us, emphasize the probabilities over the possibilities.[lviii] The probability is war until Putin dies, Ukraine is defeated, or the Russian military breaks as it did in 1917. Ukraine’s defeat is possible—but becomes probable if its Western supporters cease or curtail aid and Ukraine continues refusing to fully mobilize its manpower. The defeat of Russia’s military is possible (though perhaps not probable) because of poor leadership, weak training, and meat-grinder tactics; its manpower and equipment reserves make this difficult. Ukraine proved with its 2022 counteroffensive a sufficiently weakened Russian army is susceptible to battlefield defeats. But as Ukraine proved in 2024, such an offensive is not easily repeated against a prepared Russia when one doesn’t control the air. The situation does not leave one hopeful.