While the world marked the 70th anniversary of Hitler’s defeat, Ukraine’s president, Petro Poroshenko, sent his embattled compatriots a mixture of messages about the past and their identity. His words and gestures had to be carefully crafted because of his country’s role as a battleground between Nazis and Soviet forces, with Ukrainians fighting on both sides and suffering terribly. Sensitivity was running extra-high because, in today’s war between his government and separatist rebels, many combatants feel those old battles are still in progress.