After more than two years of fighting, Russia’s invasion of Ukraine has bogged down into a bloody impasse. Both countries continue to spend substantial resources to gain territory, but their advances are rare and small. Sometimes they are quickly reversed. Neither side has the resources to achieve a decisive victory on the battlefield. Both are incurring heavy casualties every day.

Typically, academics describe such situations as “mutually hurting stalemates,” and they often foster the conditions that cause parties to negotiate. If the warring actors lack the means to alter the trajectory of fighting, they often rethink how much they can accomplish by force. And if faced with an increasingly costly and indefinite deadlock, they start to consider previously unpalatable concessions. The result can be bargaining space that did not exist before.

Yet this war has not reached a stage where a negotiated termination is possible, even in principle. To make peace in a conflict, both parties have to be willing to accept each other’s minimum demands. And despite the mutual lack of progress, neither Russia nor Ukraine can swallow each other’s requirements. Kyiv, for instance, cannot accept Russia’s demand for new leadership. Moscow cannot accede to Ukraine’s demand for reparations. Both sides will not give up land.

No amount of creative diplomacy can alter these facts. For both countries, fighting on remains preferable to making a settlement. And unless there is a drastic change on the battlefield or in one of the state’s governments, it is highly unlikely that that the two sides will revise their requirements in the long term, either. The Russians appear incapable of conquering the lands they have laid claim to, but the Kremlin is dug in, and it is insulated from the kinds of political pressure a costly war would normally produce. The Ukrainians cannot simply give up millions of their citizens to Russian subjugation (one of Moscow’s central demands) while they can still defend them by fighting. When this war ends, it is unlikely to be with a compromise agreement that grants Russia many of its demands. Instead, it will either be because Ukraine grows strong enough to wrest control of newly conquered lands and has the capability to deter Russia from attempting to regain them or after the Kremlin prevails more on the battlefield—and Ukraine’s resources are only enough to defend what independent land remains.

BLOODY BARGAINS

War is a mutual act. One side can unilaterally initiate hostilities, as Russia did, but war would not occur unless the other side chooses to fight back. This choice is rooted in a belief that fighting will yield a better outcome than what the other side is willing to offer. Peace is similarly reciprocal. Both sides must agree to the terms offered; otherwise, they will continue to battle. For a group to consider a peace agreement, its terms can be no worse than what it expects to gain by fighting.

Before a war begins, each side’s expectations about the conflict are based on intelligence estimates, prior experience, analysis of military maneuvers, and guesses about their opponent’s (and their own) morale, state of readiness, and political situation. After the fighting starts, these expectations shift as policymakers gain new information about themselves and their opponents. As the historian Geoffrey Blainey memorably put it, war provides the “stinging ice of reality,” as the belligerents’ expectations collide with their actual performance. Fighting teaches each side about its real capabilities, its ability to marshal resources and organize forces, and the policies of third parties. The new information causes each actor to revise its expectations about the trajectory the war is likely to take and about how long it can stay in.

Consider, for example, the North Korean invasion of South Korea in 1950. When North Korea’s Kim Il Sung presented his plans to Soviet leader Joseph Stalin and Chinese leader Mao Zedong, he convinced the former to provide support by arguing that his Soviet-supplied and Soviet-trained army would overrun South Korea in a matter of weeks and that the United States would not have enough time to intervene. But U.S. President Harry Truman’s rapid dispatch of forces and success at organizing an international coalition under the aegis of the United Nations surprised him, as did U.S. General Douglas MacArthur’s daring landing at Inchon—which shattered the invading army and reversed the course of the war.

Such shifts invariably force states to change their military strategy and war effort, rethink what they would agree to in exchange for peace, or both. Confronted with an unexpectedly underwhelming showing on the battlefield, a belligerent with untapped manpower and resources often mobilizes for a larger effort. After vacillating for weeks, for example, Mao resolved to intervene in the war as it became clear that MacArthur could reach the Yalu River. (His intervention dealt the United States its own reality check, pushing U.S. forces back down the peninsula.) When expanding the war effort is not feasible or practical, states tend to lower what they might demand for a peace agreement. But states always weigh what peace would look like against continuing to battle. Fighting against all odds can be rational for actors if the consequences of ending the conflict seem worse than continuing it.

States also consider whether a potential peace agreement would stick. An actor might agree to stop fighting, but if it does not consider the outcome final its opponents have no reason to believe that it would not attempt to revise the terms at the first opportunity. Terms that leave one side considerably weaker than the other are especially likely to invite revisionism, because they undermine the weaker party’s deterrence. The 1973 Paris Peace Accords were supposed to establish peace in Vietnam and split the country between the North and the South. But by paving the way for Washington to withdraw, they severely weakened the latter’s security. Two years later, the North Vietnamese resumed their invasion and finished the conquest of South Vietnam. This case illustrates what will likely to happen if negotiators attempt to freeze the current war along the lines of control and leave Ukraine to fend for itself. At some point, a revanchist Russia will move in again.

NO QUARTER

When Russia invaded Ukraine, it had four major aims. The first was to conquer land. Although Moscow never fully spelled out its territorial ambitions, Russian President Vladimir Putin’s references to the imperial idea of Novorossiya, or “New Russia,” gave analysts a sense of what the Kremlin wanted. (His recognition Donetsk and Luhansk as independent states, which happened shortly before the February 2022 invasion, was similarly telling.) Novorossiya encompasses the Ukrainian provinces of Donetsk, Kharkiv, Kherson, Luhansk, Mykolaiv, Odessa, and Zaporizhzhia—that is, Ukraine’s entire east and south—and Russia’s invasion plans featured a massive multipronged attack designed to capture these territories. Conquering these provinces would create a land bridge to the Crimean Peninsula and to the pro-Russian Moldovan breakaway enclave of Transnistria. It would also deprive Ukraine of access to the Azov and Black Seas.

The second aim was what Russia called “denazification”—which meant regime change. The Kremlin wanted to topple Ukrainian President Volodymyr Zelensky’s freely elected government and replace it with one friendly to Moscow. To that end, the invasion featured a drive toward Kyiv. “Denazification” also meant de-Ukrainization: purging society of Ukrainian history, culture, and the Ukrainian language. Putin regarded each of these as foreign-imposed artificial constructs.

The third aim was demilitarization. This entailed making the Ukrainian military so small that it would be nearly worthless, including by placing restrictions on the number and type of weapons Ukraine could field. Demilitarization also meant prohibiting Kyiv from producing most kinds of weapons, as well as from importing Western arms of any significance.This last prohibition tied into Moscow’s final aim: neutrality. Russia wanted to forbid Ukraine from joining NATO or from pursuing political or economic integration with the European Union.

Collectively, these four goals amounted to the dismemberment and subjugation of Ukraine. More than a third of its territory and about half of its population would be formally annexed by Russia. The landlocked rump state would be made subservient to Moscow, governed by a puppet regime that lacks any means of pushing back against Russian commands. Having lost about two-thirds of its prewar GDP, the country would be almost entirely dependent on Russia for its economic survival. (Roughly two-thirds of Ukraine’s prewar GDP comes from the territories Moscow wants to annex.)

Despite these grotesque demands, Kyiv agreed to negotiate with Russia during the initial days of the invasion, when Moscow’s blitzkrieg threatened to quickly defeat the Ukrainian armed forces. Ukraine was even willing to offer significant concessions. It agreed to proclaim itself a neutral state and to remain nonaligned militarily, provided Russia withdrew and the permanent members of the UN Security Council (along with Canada, Germany, Israel, Italy, Poland, and Turkey) give it international security guarantees and promote its membership in the EU. But these talks quickly collapsed. Kyiv’s offers came nowhere near Putin’s maximalist requirements, and Ukraine was able to stop Russia’s advances. And on April 1, after Russia withdrew from the suburbs north of Kyiv, Ukrainians uncovered the first evidence of atrocities committed by Russians in occupied territory, shocking the world and making it clear what Moscow would do to Ukrainians under its rule. This stiffened Kyiv’s resolve not to offer territorial concessions and to fight to defend every inch of the country.

The country’s resolve grew even stronger when, in the summer and fall of 2022, it launched counteroffensives that compelled the Russians to withdraw from Kharkiv province and the city of Kherson. This success also strengthened international support for Ukraine, as foreign governments began to believe that the country could effectively fight back. These victories even prompted Kyiv to increase its ambitions. The government loudly promised to liberate all Ukrainian territory, including land taken by Russia in 2014, and demanded reparations.

But the Kremlin retained its initial goals. Rather than scaling back its aims, Russia reacted to the setbacks by ordering a massive mobilization of men and materiel and throwing both into combat, hoping to improve its war trajectory. It succeeded. Moscow killed thousands of its own soldiers, but it took the Ukrainian city of Bakhmut in May 2023, demonstrating its willingness to bear unimaginable costs. Russia annexed every Ukrainian province even partially under its control (Donetsk, Kherson, Luhansk, and Zaporizhzhia). It made Ukrainian recognition of these annexations a precondition for any peace talks. It also began demanding amnesty for any war crimes and—to add insult to injury—that the West pay for the costs of war. A year of fighting, then, only drove the two sides further apart.

NO JUSTICE, NO PEACE

The second year of the war was supposed to resolve a major unknown: were the Ukrainians, supplied and partially trained by the West, capable of dislodging the Russians from heavily fortified positions? The answer, unfortunately, turned out to be no. Kyiv’s 2023 counteroffensive largely failed to liberate more territory. This defeat also added credence to the idea that Putin can prolong the war until Western support collapses.

But although Ukraine has struggled, Moscow has not done much better. Russia captured the Ukrainian town of Avdiivka, yet it has failed to make real gains elsewhere. It has continued to incur high casualties—losing more than 16,000 soldiers in the fight for Avdiivka alone. Many of its Black Sea ships have been destroyed by Ukrainian drones and missiles.

In response to their respective struggles, both countries are mobilizing hundreds of thousands of soldiers. But even so, neither seems to have any prospects for significant breakthroughs on the battlefield. They are in what appears to be a classic mutually hurting stalemate, when peace deals should become possible.

And yet it is extremely unlikely the two sides will strike an agreement. Simply put, Russia’s demands are too extreme for Ukraine to countenance, and they are unlikely to soften. Putin is ideologically committed to subjugating Ukraine, and his political invulnerability makes him almost entirely insensitive to the war’s financial and human costs.

Consider Russia’s territorial designs, one of the Kremlin’s four fundamental aims. What Moscow desires is not only Novorossiya’s land—valuable and rich in resources though it is—but also the millions of Ukrainians who live there. To strike a peace agreement with the current Russian regime, Ukrainian officials would have to agree to abandon these people to Russian control, and the Kremlin’s policies in occupied territories make it clear how horrible that would be. In seized towns and cities, Moscow represses everyone connected with the Ukrainian government, security, or military forces, as well as anyone suspected of nationalist sympathies. Sometimes it outright kills them. Moscow requires that Ukrainian children study in schools designed to teach them false history about their country, to despise their Ukrainian origins, and to prove their loyalty to Russia. Children of “problematic” families have been deported and dispersed in Russia, never to be heard of again. The Ukrainian government will not make concessions that allow these atrocities to take place on an even greater scale while there is any hope of avoiding them.

The government also cannot sign off on the cultural elements of “denazification.” In the places where Russia has power, it has systematically destroyed libraries and monuments. It has worked to settle Ukrainian territory with Russians or ethnic minorities from the Russian hinterland. These strategies are not new for Moscow—they were pursued by tsars and communists alike—and they work, albeit at an unspeakable human cost. But Kyiv will not permit them to expand any further than Russian force allows. In fact, even if the West were to curtail its aid to Kyiv, it is unlikely that Ukraine’s leaders would agree to a peace deal on these extreme terms.

Given Moscow’s insistence on regime change, an agreement with Russia would also require Ukraine’s current leadership—the very people who would negotiate such a deal—to step down. These officials have no incentive to give up their positions, especially since Ukrainians show no signs of souring on them. The Ukrainian presidency enjoys widespread support and trust, and the country’s people are uninterested in trading land for peace. Ukrainians also remain firmly committed to democracy, with 79 percent preferring it to some sort of strongman rule. The war has also contributed to a national identity that will have a strong anti-Russian component for a long time. The expression of this identity will be in the Ukrainian language—enrollment has skyrocketed in Ukrainian language courses in the country’s predominantly Russian-speaking areas—and in a history of having fought against Moscow.

Since deterring Russia is the only way to avoid ceding territory and people or to avoid giving in to “denazification,” Ukraine will, by definition, have to refuse Russia’s third demand: demilitarization. Kyiv must maintain a sizeable army in order to keep fighting off the Kremlin—perhaps with universal conscription, modeled on the Israeli or Swiss variants—complete with a large and modern equipment base supplied by a robust defense industry. It will need to develop and maintain a significant air force and navy, as well. And given Russia’s massive advantage in size and resources, Kyiv would almost certainly need to avoid becoming neutral. Kyiv must rely on its Western partners for help equipping its armed forces. It will also want external security guarantees. Although it may settle for bilateral arrangements, no agreement will be as desirable or sought after as is NATO membership, which 80 percent of Ukrainians want.

For there to be any chance of a negotiated settlement, the Russians would have to accept that their demands are far too extreme. But the Kremlin is not interested in peace. If it was, it would not take such extreme positions in the first place, including that Ukraine cede more territory before talking. For now, all the Kremlin’s public statements about being willing to negotiate are merely Kabuki theater designed to paint Moscow in a favorable light in order to undermine international support for Ukraine.

A LONG WAR

It is impossible to entirely rule out a Russian-Ukrainian agreement. Leaders do not often lie about their demands, but they are strategic in what they say out loud, and Putin and Zelensky may be privately willing to settle for less than they claim. Wartime events could also push the two states to reconsider their stances. The extraordinary casualties on the Russian side, for example, could lead to mutinies, and if the war seems to be at an impasse for very long, a palace coup could install more accommodating leadership. A Ukrainian attempt to mobilize hundreds of thousands of new troops might lead to a significant decline in support for the war effort, which could make that country’s government willing to contemplate territorial concessions.

But such outcomes are improbable. Both Kyiv and Moscow have been remarkably consistent in reiterating their key demands, and neither has backed off promises of absolute victory. They are digging in for the long haul, cultivating supportive external sources of aid—in Russia’s case, Iran and North Korea (and potentially China), and in Ukraine’s case, the West. Neither state appears poised to change course.

The most likely outcome, then, is continued fighting. Moscow will keep attempting to conquer much of Ukraine. Kyiv will keep fighting back. Right now, the Russians have the initiative on the battlefield and have declared another round of mobilization. Aid for Ukraine, by contrast, is stalled in Congress, and the West’s unity is shaky. But the Russians have been unable to produce enough new equipment to replace their losses and are reliant on dwindling Soviet-era stocks. Its economy continues to be squeezed by ever-tightening sanctions. Some Western states have resumed supplying Ukraine, and the government is mobilizing. Russia may gain control of some Ukrainian territory, but Kyiv will remain independent, as will most of the country.

The Russian regime will, therefore, remain dissatisfied with its borders, much as it has been since 1991. It will continue to be a revisionist state bent on expanding its territory—by force if necessary. Any durable peace must thus be based on deterrence, not satisfaction with the status quo. It requires that Ukraine be strong enough, both internally and through its partnerships, to repel Russian attacks. Putin is right about one thing: Ukraine’s sovereignty exists only as far as it can be defended from Moscow’s grasp.