Ukraine’s Summer of Adaptation

Throughout the spring and summer of 2026, Russia tried to encircle Ukraine’s “fortress belt” in the Donetsk region. One group was to advance from the Lyman area in the north, another from Dobropillya in the southwest, and the two were meant to meet near Barvinkove in the Kharkiv region. Moscow hoped to isolate Sloviansk and Kramatorsk without a frontal assault on either city, but by autumn the northern half of that plan had collapsed.

It collapsed north of Lyman. There the 3rd Army Corps under Brig. Gen. Andriy Biletsky ran Operation Vivaldi for months in near silence; Kyiv acknowledged it only on September 15. Ukrainian officials have since given figures of between roughly 140 and 176 square kilometers (54 and 68 square miles) retaken.

The Washington-based think tank Institute for the Study of War (ISW), which counts only geolocated gains, gives a lower number, but notes that part of the advance was probably made earlier and not reported. In its assessment, Vivaldi broke the northern arm of the Russian pincer and cost Moscow both ground around Lyman and a central element of its campaign plan, including the approach to Sloviansk from the northeast.

The operation is not over. Biletsky has said that Operation Vivaldi, like its namesake’s best-known concertos, has four seasons. ISW believes the third is now underway.

Moscow’s own figures bear little relation to independent counts. At the OSCE, the United Kingdom dismissed Russia’s claim to have taken more than 670 square kilometers (259 square miles) in September. By ISW’s count, Russia ended that month with a net loss of about 81 square kilometers (31 square miles).

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In other sectors, Russian pressure continued without an operational result. Russian units attacked daily on the Pokrovsk and Kostyantynivka axes, yet the Center for Strategic and International Studies (CSIS), another Washington think tank, measured their progress in tens of meters per day. The Zaporizhzhia front stayed largely stable, and the northern and Kupiansk sectors served mostly to pin Ukrainian forces in place.

One plan, several chains of command

What made Vivaldi work was less any single weapon than the way different structures were combined. The 3rd Army Corps planned and led the operation, using drones, ground robots and mechanized assaults under one headquarters. Attached to the corps were the 66th Mechanized Brigade, a tank group from the 8th Regiment of the Special Operations Forces, the 10th “DOZOR” mobile border detachment and Artan, a special unit of Ukraine’s defense intelligence (HUR), which fought in one of the operation’s phases. Army, special operations, border guard and intelligence units answer to different chains of command, yet here they worked to a single plan, and commanders on the ground credit the motivation of their troops for holding it together.

On the Zaporizhzhia axis, Artan, led by Col. Viktor Torkotiuk (call sign “Titan”), had been attacking Russian positions long before Vivaldi was made public. The unit reported offensive actions near Stepnohirsk as early as February, and in mid-May, together with neighboring units, it cleared key parts of the settlement. According to HUR, Russia sent VDV reconnaissance troops, considered elite, to retake Stepnohirsk in late May. Artan let them come closer and caught them in an ambush. The Russians refused an offer to surrender and opened fire; the group was destroyed without Ukrainian losses. Holding Stepnohirsk keeps Russian artillery and drone crews further from the city of Zaporizhzhia.

Artan’s ground robots did a large part of the carrying. According to the unit, over the summer they covered about 4,258 kilometers (2,646 miles) on the front line, delivered more than 41 tons of supplies to forward positions, transported captured Russian soldiers and pulled 45 Ukrainian servicemen out from under fire. Torkotiuk describes the purpose plainly: “Technology is transforming the combat capabilities of frontline units. Innovative logistics frees up capacity and forces for active operations and offensive actions.”

The most telling figure, though, is the split among the evacuated. Only 10 were Artan’s own; the other 35 came from neighboring units. A robot fleet run by one unit was serving the whole sector, and that is the model robotic logistics will need if it is to grow beyond individual brigades.

Strikes in depth

At the same time, Ukraine stepped up its campaign against Russian logistics and fuel. Drone units of the Unmanned Systems Forces, commanded by Robert “Madyar” Brovdi, and of the Special Operations Forces put the land corridor to Crimea under fire. Brovdi said that from June 7 Russia’s “Vostok” group officially banned military cargo traffic on the R-280 highway through Mariupol, Berdiansk and Melitopol to Simferopol. Ukrainian long-range drones hit the Omsk refinery, Russia’s largest, some 2,500 kilometers (1,553 miles) from Ukraine, in July and again in October. On Oct. 9, they reached the refinery in Ukhta in the Komi Republic.

Manpower

Ukrainian and Western estimates of Russian losses are close. CSIS puts them at 30,000 to 34,000 killed, wounded or missing per month in 2026, while Russia recruits about 27,000 people a month.

Oleh Ivashchenko, head of HUR, told The Times that Russian generals have asked Putin to mobilize 800,000 people after the September State Duma elections. Daily recruitment, he said, stands at about 1,000 to 1,200, occasionally rising above 1,500.

Limits of the Ukrainian model

None of this makes Ukraine’s position comfortable. Drones and robots save infantry, but they do not replace it, and the army still lacks the people to rotate units out of the line as often as it should. Ground robots come in many models from many manufacturers, which speeds up innovation but complicates training, spare parts and repair, and Russian drones and electronic warfare already hunt them. Ukraine builds most of its long-range strike drones itself, yet it still depends on partners for air defense missiles, satellite intelligence and much of the money behind its own production lines.

Risks: the front and Washington

Russia is likely to resume pressure on the Pokrovsk and Kostyantynivka axes this autumn, relying on infantry infiltration rather than armored thrusts. A breakthrough looks unlikely at present force levels, but constant attrition will test Ukrainian manpower further. Russia will also continue its winter strikes on Ukraine’s power grid, one of the few tools it has that can affect Ukrainian society quickly.

Washington has become the bigger uncertainty. In mid-September President Donald Trump announced that Russia and Ukraine had agreed to stop striking each other’s energy facilities, although neither side had signed anything. The Financial Times reported that Putin did not want a truce before winter, expecting attacks on Ukraine’s grid to force concessions from Kyiv. Zelensky said Ukraine would stop its strikes if partners could guarantee that Russia did the same. The Kremlin welcomed the idea, asked for sanctions to be lifted and kept hitting Ukrainian power plants.

On Oct. 9, Trump announced a deal with Putin to buy Russian diesel, starting with more than 300,000 tons and rising to several million. The Associated Press described it as a stunning reversal of years of American pressure on Moscow. Only weeks earlier Trump had signed a sanctions law that directs his administration to penalize the main buyers of Russian oil and gas. With this deal, the United States becomes a buyer of Russian fuel itself. Zelensky called it “a weak decision by strong partners.” Two days later the Financial Times reported that Washington had threatened to halt purchases of American weapons for Ukraine under PURL unless Kyiv stopped striking Russian refineries.

So Ukraine is being asked to drop the one form of pressure that is visibly hurting Russia’s war economy, while Russia keeps its winter campaign against Ukrainian energy and gains a new buyer for its fuel. Whatever the intent in Washington, the Kremlin is likely to conclude that high fuel prices in an American election year can win it relief its troops could not win at the front.

Europe would pay for that conclusion too. Oil revenue pays for Russia’s army, and each month of relief gives Moscow more time to rebuild forces that European governments already plan against on NATO’s eastern flank. If pressure on Washington works for Russia in Ukraine, Moscow has every reason to try it against European capitals next.

What NATO should take from Ukraine

Allied militaries follow this war closely, yet most of what Ukraine has learned this year exists in the habits of its commanders, engineers and units rather than in written doctrine.

The 3rd Army Corps achieved operational surprise on a battlefield watched by thousands of drones and satellites, because deception and information discipline were planned as carefully as fires. Artan’s figures put a number on something allied logisticians have so far mostly modelled: ground robots carrying a real share of frontline supply and casualty evacuation, across unit boundaries, so that infantry can be used for fighting. Further back, the campaign against the R-280 and Russian refineries has been fought largely with Ukrainian-made drones, cheap enough to use in quantity and able to reach targets 2,500 kilometers away.

NATO armies have rehearsed much of this in exercises. Ukrainian units have done it for months against the army the alliance is preparing to deter. If allied planners keep those units at arm’s length and treat Ukraine as a source of reports rather than a partner in force design, they will learn the same lessons later and pay more for them.

What is at stake this winter is whether Russia can win through pressure on Washington what it failed to win at Lyman. If Ukraine’s deep strikes are traded for cheaper diesel while Russian missiles keep hitting Ukrainian power plants, Moscow gains an operational advantage without taking a single village.

Russia still has more men and more artillery, and this summer it could not make them count. Whether that remains true now depends on Ukraine’s partners: on whether they leave it the means to strike deep, and whether they treat what Ukraine has built as part of Europe’s own defense.