Russian forces managed to capture around 68 square miles of Ukraine in April. But it cost them 4,800 vehicles and more than 36,600 dead and wounded troops, according to one statistician who collects data mostly from official Ukrainian sources including the general staff in Kyiv. In the same month, Ukrainian losses were “minimal,” concluded analyst Konrad Muzyka of Rochan Consulting in Poland. Ukraine sprawls across 233,000 square miles, 19% of which is under Russian occupation. At the current rates of advance and loss, the Russians would capture the rest of Ukraine in the year 2256 at the cost of 101...