t’s winter in Ukraine again. The snow is piling up, the temperature is dropping, and the days are short. During the long nights, nearly two years into the full-scale war, the skies above the entire 600-mile frontline are filled with Ukrainian and Russian drones. In past centuries, the machinery of war would grind to a halt when harsh conditions pushed human endurance to its limits. The two most famous military campaigns in this part of the world—Napoleon’s invasion of Russia in 1812 and Hitler’s in 1941—succumbed to devastating casualties as the season changed. Today, the hapless infantry who still fill trenches and strongpoints across Ukraine are contending with the same unforgiving winter. But the drones that have come to dominate this war are limited only by their battery lives—shortened by the cold—and the availability of night-vision cameras.