The tone is dark, even angry. “The situation is getting worse every day.” Almost four months after Ukrainian troops launched a lightning offensive into the Russian region of Kursk, text messages from soldiers fighting there paint a dismal picture of a battle they don’t properly understand and fear they might be losing. They speak of dire weather conditions and a chronic lack of sleep caused by Russia’s constant bombardment, which includes the use of terrifying, 3,000kg glide bombs. They’re also in retreat, with Russian forces gradually retaking territory. “This trend will continue,” Pavlo wrote on 26 November. “It’s only a...