Nobody knows how or when the war will end in Ukraine, but it’s clear that right now Russia isn’t winning. According to Western governments and private analysts, Moscow failed to achieve its initial goal of a lightning strike into Kyiv to take down the government. And success for its Plan B, a scaled-down offensive to push Ukrainian forces back in the east and southeast of the country, looks increasingly difficult.
Some things that seemed highly probable at the start of the war, such as the collapse of the Ukrainian state, now are seen as unlikely. Ukraine is in an existential fight, said the chief of the British defense staff, Adm. Tony Radakin in a speech in London on Monday, “and it is going to survive.”
In this latest phase of the war, tank battles are being supplanted by artillery-dominated exchanges. The Russians are undertaking offensives in some places, including in the eastern region of Luhansk. They finally overcame the last remaining Ukrainian holdouts in the southern port city of Mariupol. Elsewhere, the Ukrainians are counterattacking, most notably in the north beyond Kharkiv.
“The war is entering a protracted phase,” Ukrainian defense minister Oleksii Reznikov told European Union defense ministers on Tuesday. He said there were “many indications of Russia preparing for a long-term military operation,” including engineering and fortification works in the Kherson and Zaporizhzhia areas.
Russian invasion
Areas no longer controlled by Ukraine as of May 18
RUSSIA
Areas abandoned by Russian forces
Controlled by or allied to Russia
BELARUS
Russian advances
Ukrainian counterattacks
Kharkiv
Ukraine territory, recognized by Putin as independent
POLAND
Kyiv
Luhansk
Dnipro
Lviv
Donetsk
UKRAINE
Mariupol
Kherson
Transnistria
Sea of Azov
Odessa
MOL.
CRIMEA
ROMANIA
Sevastopol
Black Sea
200 miles
200 km
Russian invasion
Areas no longer controlled by Ukraine as of May 18
Areas abandoned by Russian forces
Russian advances
Ukrainian counterattacks
Controlled by or allied to Russia
Ukrainian territory, recognized by Putin as independent
200 miles
RUSSIA
200 km
BELARUS
Kharkiv
POL.
Luhansk
Kyiv
Lviv
Dnipro
UKRAINE
Donetsk
Kherson
Mariupol
MOL.
Transnistria
Odessa
CRIMEA
Sevastopol
Black Sea
ROMANIA
Russian invasion
Areas no longer controlled by Ukraine as of May 18
Areas abandoned by Russian forces
Russian advances
Ukrainian counterattacks
Controlled by or allied to Russia
Ukrainian territory, recognized by Putin as
independent
200 miles
200 km
RUSSIA
BELARUS
Kharkiv
POL.
Kyiv
Lviv
Donetsk
Donetsk
Dnipro
Kherson
Mariupol
MOL.
Transnistria
Odessa
CRIMEA
Sevastopol
Black Sea
ROMANIA
Even so, sooner or later, the war will end in a cease-fire or armistice. Given the new realities on the ground, here are five possible scenarios on where the conflict could go, some of which could follow from another.
1. A Russian collapse
Highly motivated, well-armed and tactically adept Ukrainian forces have exploited weaknesses in the Russian military. The Russians have struggled with weak logistics and with coordinating different elements of their campaign. They have suffered from poor equipment and training, and in places low morale. Among the tens of thousands of estimated Russian casualties, their officer corps has been seriously weakened, according to Western analyses.
Most Western analyses of the war suggest that Moscow’s Plan B—to concentrate forces in the east and southeast and enlarge its foothold in the Donbas region—is going much more slowly than the Russians hoped. Moscow’s apparent plan to encircle Ukrainian forces looks unachievable, according to some. Meanwhile, long-range Western M777 cannons and other weaponry have also moved into the fight. The Pentagon says they are already making a difference.
The best that some analysts can find to say for Moscow’s military performance to date is that it hasn’t fallen apart. “You could argue that the Russians have done pretty well in holding their army together given the pressure that they’re under,” said Lawrence Freedman, professor emeritus of war studies at King's College London. But, he adds, “armies can be brittle.”
Western intelligence officials have noted significant combat refusals by Russian troops. They have also said that Russian units that were mauled in the battle for Kyiv have been thrown back into battle, often with poorly trained recruits. U.K. defense intelligence says the use of auxiliary forces—such as fighters from Chechnya—have made it even more difficult for Russia to coordinate forces.
“I think here the scenario that’s possibly being underestimated a bit is the possibility of real Russian collapses,” said Eliot Cohen of the bipartisan policy research group Center for Strategic and International Studies in Washington. This could involve widespread refusals to enter the fight, absences without leave or disorderly retreats.
Even outcomes short of that would likely have consequences in Moscow, said Mr. Cohen. “I think at some fundamental level, Putin’s already lost,” he said. “I personally find it difficult to imagine him hanging onto power for a very long period of time.”
2. A Ukrainian collapse
While the heavy damage inflicted by the Ukrainians on Russian forces has been well documented, there is less evidence for how much Ukrainian forces have suffered. Publicly available information suggests the casualties and equipment damage has been significant, but Western estimates suggest losses are a fraction of those suffered by the Russians, who were estimated by the North Atlantic Treaty Organization to have 40,000 troops killed, wounded or captured by late March.
The capture of Mariupol was a long-sought victory for Russia, after Ukrainians who were besieged at a steel works for almost three months laid down their arms. Russia’s Defense Ministry said on Wednesday that more than 950 Ukrainian soldiers there had surrendered and become prisoners of war. Moscow’s forces are also putting Ukraine under intense pressure around Severodonetsk and Lyman in the Donbas, analysts say.
Without reliable estimates of casualties and equipment losses, analysts have to look for other clues for the state of the Ukrainian military.
One benchmark analysts use is how they are fighting. “Do they seem to be fighting competently and intelligently, and are there signs of failure?” says Phillips O’Brien, professor of strategic studies at the University of St. Andrews in Scotland, who added that he didn’t see those signs. The effectiveness of Ukrainian forces will also be boosted by Western equipment pouring into the country.
Michael Clarke, former director of the Royal United Services Institute, a London security think tank, said President Biden’s request to Congress for $33 billion of long-term military aid is a signal that he “is going to do whatever it takes to ensure that Ukraine does not go under. That makes it much less plausible that Ukraine could be beaten.”
“I don’t think a Ukrainian collapse is likely. I’d almost rule that one out,” said Mr. Freedman of King's College London. “They have the motivation and the momentum.”
3. Quagmire
Wars often develop into stalemates that neither side dares lose. Western officials have warned the conflict could last into next year or well beyond.
“War is often or can be a process of competitive collapse where victory goes to the side still standing, even though both are suffering terribly. That was certainly what happened in 1918,” said Mr. Cohen, speaking of the end of World War I.
A stalemate, he said, is “conceivable if you really think that the Russians are well dug in and tenacious and will be able to generate replacements for the quite terrible losses they’ve taken.” He said he finds that unconvincing. He said a more likely scenario is that the Ukrainians exploit their mobility and tactical superiority to choose places to attack and penetrate Russian lines.
Several analysts said they expect that if Ukraine can withstand the current Russian offensive in the Donbas, the Ukrainians will intensify their counteroffensive in the next few weeks, starting a critical phase of the war. Mr. Clarke said that Russia’s army is too small to achieve even its limited objectives in Ukraine. The key longer term for Moscow is whether recruiting efforts bear fruit and whether another 150,000 to 180,000 troops can be brought into its standing army. Given the need for training, new recruits wouldn’t arrive on the battlefield until close to the end of the year. “If next year the Russians can have a bigger mobilized force, then we get into the stalemate scenario,” he said.
4. Ukrainian advances
After redirecting its forces to the east and southeast, the Russians appear to have rushed to mount piecemeal offensives, sometimes using troops that had been pushed back from Kyiv, instead of biding their time and mustering a large-scale force.
“It does look like the Russian advances are going to peter out relatively soon,” said Mr. O’Brien. “At some point they’ll stop moving forward, and the question is, will the Ukrainians be able to push them back?”
In this phase, Western arms are hugely important, analysts said. A senior Pentagon official said on Monday that Ukraine had reported that 74 of the 90 M777 artillery cannons that the U.S. supplied Ukraine are in forward positions around Kharkiv and elsewhere.
The long range of these howitzers allows the Ukrainians to attack Russian forces without putting themselves within firing range. Ukraine is also getting other Western equipment, including Switchblade and Phoenix Ghost drones. “The combination of drones and artillery is quite powerful,” said Mr. Freedman.
If the Ukrainians do advance, the next question is where they stop. The minimum target for Ukraine would be the lines of control in place on Feb. 23, the day before the Russian invasion. That would leave Moscow in control of two enclaves in the Donbas and Crimea, which it annexed in 2014.
The analysts said if Ukrainians are successful, stopping would be a political challenge for Ukrainian President Volodomyr Zelensky. The temptation would be to push the Russians farther back.
Offensive operations are more challenging than defensive ones. Advancing through zones where the Russians have been long entrenched, in the Donbas and particularly into Crimea, a great prize for Russian President Vladimir Putin, would be ambitious for Ukraine. Outside pressure on Mr. Zelensky, particularly from Europeans, to limit the advance would likely grow.
“At the point at which the Western allies are split on whether we are trying to win the war or end it...it’s harder for the Ukrainians to go on the way they have,” said Mr. Clarke.
5. Escalation
A lot of Western discussion, particularly in Europe in the lead-up to the war, involved making sure Mr. Putin had an off ramp. Some analysts now worry about cornering the Russian leader lest he lashes out and escalates the conflict—for example by introducing tactical nuclear or chemical weapons into the battlefield.
Western analysts say this is possible, but unlikely. Even if battlefield nukes were used, the conflict wouldn’t automatically escalate into an exchange of intercontinental ballistic missiles between Russia and the West.
The use of nuclear weapons by Russia would break a taboo against their use in war that has held since 1945. Such would be the reaction, Mr. Cohen said, that “my guess is that if Putin actually went that far, he would find his orders being slow-rolled by his immediate subordinates.”
Using such weapons would attract widespread international condemnation and likely elicit a response to further isolate the Russian economy, including by potentially introducing so-called secondary sanctions that would target not just Russian entities but also any company doing business in Russia.
The primary factor against using such weapons, analysts said, is that it would provide no advantages in the fighting—where both sides are close to each other and where there are no large-scale concentrations of Ukrainian forces.
“One battlefield nuclear weapon doesn’t do anything for you. Lots of battlefield nuclear weapons just creates a lot of fallout and is likely to take out some of your own people,” said Mr. Freedman. Chemical weapons are hard to direct and risky for your own troops, making them even more ineffective.
Two other motives for using them, including away from the battlefields, would be to terrorize the country, in an effort to influence decision makers in Kyiv or to encourage Western governments to pressure Ukraine to pursue peace. Both avenues are hypothetically plausible but unlikely, analysts said.
Any use of these weapons would likely draw the West deeper into the conflict. A nuclear response from Western powers would be unlikely, analysts said, but a conventional military response probable.
The current red lines that are stopping Western forces from carrying out air operations in Ukraine would likely fall away and a no-fly zone would become a possibility. Mr. Cohen said Russia’s Black Sea fleet could become a potential Western target. Given the struggles of the Russian air force against Ukraine, a rational actor in Moscow would want to avoid direct engagements with the U.S. and other Western air forces.
That raises the question of whether Mr. Putin is a rational actor. “If Putin wants to do something completely irrational, he might, but that doesn’t mean we’ve got a rational way of stopping him,” said Mr. Freedman.
Write to Stephen Fidler at stephen.fidler@wsj.com