Jens Asbjørn Bøgen
The US think tank credits a five-month counteroffensive codenamed Operation Vivaldi with dismantling Moscow’s offensive plans.
Northern Donetsk Oblast has bled Ukrainian ground for 18 months, with Russian forces grinding steadily toward the fortress cities of Sloviansk and Kramatorsk.
This fall, that pattern quietly reversed.
In a special report published October 8, the Institute for the Study of War, a Washington think tank, concluded that “Ukrainian forces have defeated the 2026 Russian campaign to seize Donetsk Oblast.”
The think tank credited a five-month counteroffensive codenamed Operation Vivaldi, run by the country’s 3rd Army Corps in the Lyman direction of northern Donetsk.
By September 30, the corps had pushed Russian forces back across the Zherebets River, a natural barrier east of Sloviansk, returning 176 square kilometers of occupied territory to Ukrainian control, according to Ukrainian military sources.
The gain erased roughly 18 months of Russian advances in northern Donetsk. The 3rd Army Corps said its latest phase alone cost Russia more than 2,000 troops and sent over 250 Russians into captivity.
“The idea that ‘Russians don’t surrender’ from movies in practice turned into entire units surrendering in full, including officers, pilots and artillerymen,” Brigadier General Andrii Biletskyi of the 3rd Army Corps said in a video address reported by The Kyiv Independent.
Small, patient, geometric
A paper published October 9 by Col. Timothy Price, Capt. Patrick Visser and Capt. Andrew Carter for the Modern War Institute at the US Military Academy at West Point examines modern warfare but uses the Ukrainian 3rd Army Corps as a case study.
The three officers argue that the corps’ defeat of the Russian bridgehead over the Zherebets “had little to do with maneuver warfare” in the classical sense. Instead, they write, the Ukrainians won through “systematic, geometric interdiction and positional pressure … rather than breakthrough-driven cognitive shock.”
Open source material has revealed how this has been put into practice: Ukrainian units probed for tree-lined assault lanes, sent unmanned ground vehicles ahead to blow up mines and strongpoints, then followed with infantry in armored trucks. They moved a kilometer at a time, not toward a distant breakthrough.
Not alone on the battlefield
The paper argues the method only works when the ground force gets cover from above. “Higher headquarters must degrade key enemy capabilities beyond the brigade’s reach and converge multidomain capabilities,” Price, Visser and Carter write.
In Vivaldi, that meant Ukrainian Unmanned Systems Forces striking Russian supply lines, electronic warfare teams jamming Russian drones, and the Ukrainian air force bombing Russian drone operators the jammers could not silence.
The 2023 ghost
The comparison that shadows the operation is Ukraine’s 2023 summer counteroffensive out of Mala Tokmachka in Zaporizhzhia Oblast. That operation massed Western-trained brigades and tried to drive 80 kilometers south to the occupied port of Melitopol.
It got stuck roughly 10 kilometers in, bled by Russian minefields and air strikes, and lost even those modest gains to later Russian counterattacks.
ISW’s report says Russia’s 2026 plan was broader than one bridgehead. The think tank writes that Russian forces had intended a deep encirclement of Ukraine’s Fortress Belt, the fortified cities around Sloviansk and Kramatorsk.
Russian forces were to push in from Lyman in the north and Dobropillya in the southwest, linking up near Barvinkove in Kharkiv Oblast. Operation Vivaldi, ISW concluded, has made that grand encirclement unworkable.
While fierce fighting continues further south around Pokrovsk, the northern door to Donetsk’s fortress cities has been firmly slammed shut.
