Three weeks ago, the Ukrainian army’s northeastern counteroffensive dismantled one of the Russian army’s elite units: the 1st Guards Tank Army. Now the same counteroffensive reportedly has wrecked a new motorized infantry division the Kremlin stood up a few years ago in order to help protect the 1st GTA. After suffering steep losses around Bakhmut in recent days, it’s possible the 144th Guards Motor Rifle Division no longer is combat-effective. These losses are unsustainable for the Russian army—and explain why the Kremlin is willing to risk widespread unrest as it forcibly drafts 300,000 men and speeds them to the Ukrainian...