Tusk’s casualty disclosure and Kushner’s challenge to Putin bring an uncomfortable question into the open: do the assumptions sustaining the Ukraine war still add up? Diplomacy becomes more difficult when abstractions acquire numbers. For years, the Ukraine war has been discussed through broad formulations: sufficient support, sustainable defense, battlefield momentum, acceptable terms. They provide governments with considerable room to maneuver because none requires an immediate answer to the harder question of what the war is consuming and whether that consumption can continue. Donald Tusk has now supplied a number. Speaking before the Polish parliament, the prime minister said Ukrainian partners...