Why the Donbas remains the core obstacle to a Russia-Ukraine peace deal

Why the Donbas remains the core obstacle to a Russia-Ukraine peace deal

After weeks of high-level diplomacy, Russia and Ukraine remain locked in a familiar dead end: territory. Despite renewed pressure from international mediators, both sides are refusing to shift on the future of the Donbas, the industrial eastern region that has shaped the war’s trajectory since 2014. Moscow insists that any settlement must formalise its control over all of Donetsk and Luhansk, including the roughly 2,500 square miles of land it still does not hold. Kyiv, in turn, says that ceding territory is unacceptable and would reward aggression. The dispute has become the central barrier to progress at a time when battlefield momentum, political fatigue and international impatience are reshaping the conflict, the New York Times reported.

The area Russia seeks lies in the heart of Donetsk. It includes Sloviansk and Kramatorsk, cities that have served as Ukraine’s military and administrative hub since separatist fighting erupted more than a decade ago. More than 200,000 civilians still live there, and the region is among the most heavily fortified in Ukraine. For Kyiv, relinquishing these cities would mean surrendering both symbolic ground and a critical defensive anchor. For Moscow, absorbing the rest of Donbas is central to its justification for the war and to President Vladimir V Putin’s repeated insistence that Russia must “liberate” historically Russian-speaking regions. Control of these cities would also give Russia greater security over the territory it already occupies in Luhansk and southern Donetsk.

Although Russia officially annexed Donetsk, Luhansk, Zaporizhzhia and Kherson in 2022, it has never fully controlled them. Four years into the invasion, its military has been unable to capture the remaining Donbas pocket despite heavy investment in manpower and artillery. This gap has now become a political priority. In recent weeks, Putin has reiterated that unless Kyiv agrees to surrender the region, Russian forces will “liberate these territories by force.” The message is designed to shape negotiations, but it also reflects Moscow’s broader strategy: leverage territorial demands to force political concessions while maintaining military pressure along the front.

President Volodymyr Zelensky has again ruled out territorial concessions, warning that such a deal would undermine Ukraine’s sovereignty and set a precedent for future aggression. But he also acknowledged that the United States, which is helping steer the diplomatic effort, has pushed Kyiv to “compromise” on Moscow’s demands. A recent version of a US-backed plan would have required Ukraine to cede all of Donetsk and Luhansk, including areas it still holds, along with accepting Russia’s occupation of parts of Zaporizhzhia and Kherson. The proposal was widely condemned across Ukraine as capitulation, and talks have since slowed.

The stalemate comes at a moment when neither side is able to achieve decisive gains on the battlefield. Russia has advanced modestly in some sectors but remains stretched, while Ukraine is struggling with manpower constraints and ammunition shortages. This balance of weakness has increased the urgency for outside powers, particularly Europe, to press for a cease-fire. Yet the unresolved territorial map continues to block diplomatic movement. Any agreement that gives Russia land it has not conquered risks fracturing Western support for Ukraine, while any deal that denies Moscow its aims risks being rejected outright by the Kremlin.

The war began with territorial claims, and it is now being shaped by them once more. The remaining piece of Donbas that Ukraine controls has become both a military bastion and a political red line. As long as Kyiv refuses to abandon it and Moscow insists on claiming it, the path to even a temporary settlement remains narrow. Until one side softens its position—or battlefield realities shift again—the dispute over Sloviansk, Kramatorsk and the surrounding territory will continue to define the limits of diplomacy.