SPECIAL REPORT: Ukrainian forces have defeated the 2026 Russian campaign to seize Donetsk Oblast. Russian forces intended to conduct a deep encirclement of the entire Fortress Belt from the Lyman direction in the north and the Dobropillya direction in the southwest, linking up near Barvinkove, Kharkiv Oblast. This wide encirclement would have largely completed the seizure of unoccupied Donetsk Oblast. The Ukrainian counteroffensive known as Operation Vivaldi in the Lyman direction has completely disrupted this Russian plan by inflicting an operational defeat on the northern Russian pincer. This Ukrainian success will force the Russian military to reconstitute and likely fundamentally rethink its approach to accomplish its goals in this area. There is therefore no basis to assess that Russian forces will be able to take the rest of Donetsk Oblast in any short period of time, as Russian President Vladimir Putin continues to claim, or even to forecast that Russian forces will ever be able to complete their seizure of this region by force.