As Ukraine Readies for a Second Year at War, Prospect of Stalemate Looms

WASHINGTON — As the war in Ukraine soon enters its second year, Ukrainian troops will find it much more challenging to reclaim territory from Russian forces who are focused on defending their remaining land gains rather than making a deeper push into the country, American officials say.

Over the course of the first 10 months of the war, the Ukrainian military has — with significant American support — outmaneuvered an incompetent Russian military, fought it to a standstill and then retaken hundreds of square miles and the only regional capital that Russia had captured.

Despite relentless Russian attacks on civilian power supplies, Ukraine has still kept up the momentum on the front lines since September. But the tide of the war is likely to change in the coming months, as Russia improves its defenses and pushes more soldiers to the front lines, making it more difficult for Ukraine to retake the huge swaths of territory it lost this year, according to U.S. government assessments.

All of these factors make the most likely scenario going into the second year of the war a stalemate in which neither army can take much land despite intense fighting.

“I do think that it is far easier for Ukraine to defend territory than to go on the offensive to recapture territory,” said Evelyn Farkas, a former senior Pentagon official and Russia expert. “We need to be providing Ukrainians the necessary equipment and training to do that.”

President Volodymyr Zelensky of Ukraine is expected to ask for just that when he meets President Biden and addresses Congress on Wednesday evening, his first visit outside the country since the start of the war.

Over the past six months, Ukrainian forces have slowed Russia’s advance in the Donbas in the east, reclaimed a large swath of land in the northeast, and gained control of Kherson, a major southern city. But the wins came with a heavy cost: thousands of Ukrainian soldiers killed and the expenditure of immense amounts of ammunition, in particular artillery rounds. In fact, throughout much of the year, Ukraine fired far more rounds of artillery in a week than the United States could produce in a month.

Ukrainian officials have said they plan to continue to press their counteroffensive against the Russians. The focus will be in the south, where the Ukrainian military and political leadership believe they need to make gains against Russian forces to restore critical Ukrainian territory.

American officials say Ukraine will likely avoid sending its army directly into Crimea and will instead rely on more covert operations — similar to the attack on the Kerch Strait Bridge that knocked out a key Russian supply line — and airstrikes to attack Russia’s military positions in Crimea.

Ukrainian officials have told their American counterparts that it is critical to pin down Russian forces in Crimea. If they let up pressure there, the Ukrainians worry it would allow the Russians room to move more forces or defensive equipment out to other areas, according to U.S. officials who were speaking on condition of anonymity because of the sensitivity of the discussions.

Ukraine has also been reliant on American intelligence reports that pinpoint where the Russian army is at its weakest. The Ukrainian military’s counteroffensive outside Kharkiv in September was successful in part because the Ukrainians were facing a hollowed out, unprepared Russian force. American officials do not believe that even the Russian military command knew how weak those forces were or how badly prepared they were for a Ukrainian strike.

American officials are continuing to search for weak points in the Russian lines, hunting for units on the brink of collapse, which might melt away in the face of a sustained push by Ukraine. Finding those fragile units could allow for smaller victories by Ukrainian troops, American officials said.

“What this war has shown us is that it is better not to underestimate Ukraine,” Colin H. Kahl, the under secretary of defense for policy, said in an interview.

Nevertheless, Kyiv’s ability to mount effective strikes against Russian bases and supply lines will not be enough to dislodge Moscow’s troops from the parts of the country where they have concentrated their forces.

Any smaller breakthroughs by Ukrainian forces in the next few months are unlikely to lead to a broad collapse of the Russian army, these American officials say, but Russia also is unlikely to achieve anything resembling a broad military victory in Ukraine.

Throughout the war, Russia’s advance has been hampered by a series of errors. Russian troops entered Ukraine with the intention of encircling, and then capturing, Kyiv, toppling the government of Mr. Zelensky and cutting off Ukraine’s southern access to the Black Sea. The only marginally successful one of those efforts was the attack from the south, which eventually allowed Russian troops — after a protracted battle — to take Kherson and establish a land bridge to Crimea. (Although they never reached their original objective of Odesa.) But even the southern offensive eventually stalled, and Kherson, 10 months later, is back in Ukrainian hands.

When Russian units failed to follow orders, Russian generals were forced to go to the front to shore up units. And when those generals positioned themselves near communication arrays, they disclosed their positions, allowing Ukrainian forces to kill several Russian generals, American officials say. By failing to secure air superiority, Russian troops fought the first months of the war in contested skies, forcing their pilots to launch strikes from the border and then dart back to safety in Russia or Belarus.

“This war favors the competent over the incompetent, as all wars do,” said Frederick W. Kagan, a scholar at the American Enterprise Institute who writes regularly about Russian operations in Ukraine. “The Russians have been unsuccessful because they are showing their customary incompetence.”

But American officials say there is evidence that the Kremlin is finally beginning to learn from its mistakes. It has put a single general in charge of the war — Gen. Sergei Surovikin — who American officials say is executing complicated military operations more efficiently.

In recent weeks, Ukrainian military officials have said Moscow has conducted stepped-up airstrikes on the army’s defensive lines, increasing Ukrainian casualties.

As botched as the initial Russian partial mobilization of 300,000 reservists was, the sheer numbers are now making a difference along the defensive lines. And unless those troops suffer a bad winter, which is possible with poor logistics and bad leadership, they will only shore up more by the spring, American officials said.

Russian forces are also digging into defensive positions and building trenches, and they have given up areas that require larger numbers of troops to hold, moving instead to easier-to-secure positions.

The retreat from Kherson, American officials said, is a key example of how Russia has learned lessons. While President Vladimir V. Putin initially blocked a move to retreat from Kherson, General Surovikin insisted it was necessary until Mr. Putin relented. Russia’s retreat allowed Russian forces to use the Dnipro River to protect themselves from further Ukrainian attack; the entire operation highlighted a sophisticated military execution that was unusual earlier in the war, American officials said.

General Surovikin, who has led Russian forces since October, is using a strategy that emphasizes strategic defense, these U.S. officials say. He has, so far, been able to improve defenses and inject discipline into Russian troops deployed in Ukraine’s south and east. Their current push in Bakhmut in the eastern Donbas region is limited, designed to secure better positions from which to defend against a Ukrainian counterattack.

“He’s consolidating positions, and he’s trying to build a network of trenches and a more sensible set of positions and checkpoints,” Dara Massicot, a senior policy researcher at the RAND Corporation, said in a telephone interview.

Ms. Massicot said that General Surovikin is also experimenting with new tactics for the Russian air force, including the manner with which it launches missiles at Ukraine to try to confuse its air defenses. These new Russian tactics will likely result in a stalemate, leaving both sides jostling for the upper hand if any real negotiations were to begin.

In some ways, the war is becoming one that hinges on ammunition and supplies — two basic needs that can make or break either side.

“It increasingly is a contest between the Western industrial base and Russian industrial base, with some aid from the Iranians, North Koreans and a few other countries,” said Seth G. Jones, a senior vice president at the Center for Strategic and International Studies.

With Mr. Zelensky’s arrival in Washington, the Biden administration is set to offer a new $1.8 billion arms package that would send one Patriot air defense battery to Ukraine, along with precision guided munitions for fighter jets and other weaponry, senior administration officials said. Since the start of the war in February, the United States has sent more than $20 billion in military aid to Ukraine.

The package being presented Wednesday will include air defense batteries and precision guided bombs for the first time. But even more weaponry for ground units will be needed to avoid a stalemate in the months to come, according to lawmakers and outside experts.

When the Ukrainians go on the offensive again, they will undoubtedly need more artillery and ammunition, said Representative Seth Moulton, a Massachusetts Democrat on the House Armed Services Committee who recently visited Kyiv. “But they will also need things like armored vehicles, tanks and other mobile platforms that can help them advance against entrenched enemy forces,” he said.

Ukrainian forces will also need a steady supply of anti-aircraft missiles, anti-armor systems, drones, loitering munitions — aerial systems that wait around passively in an area until a target is identified — vehicles and aircraft. They also need mundane items such as spare parts, petroleum, oil and lubricants.

“Helping them replace depleted stockpiles and broken equipment is critical,” Mr. Moulton said.

Thomas Gibbons-Neff contributed reporting from Kramatorsk, Ukraine.