Ukrainian President Volodymyr Zelensky photographed in Kyiv on April 19Alexander Chekmenev for TIME The nights are the hardest, when he lies there on his cot, the whine of the air-raid sirens in his ears and his phone still buzzing beside him. Its screen makes his face look like a ghost in the dark, his eyes scanning messages he didn’t have a chance to read during the day. Some from his wife and k