Vitali Klitschko, the mayor of Kiev, said that Ukrainian President Volodymyr Zelensky may ultimately have to hold a referendum on any plan to end the war. Klitschko said Zelensky would have to show that a majority of Ukrainians stand behind the terms of a peace deal, including potentially bitter territorial concessions, in an interview in Sunday’s edition of Italy’s Corriere della Sera daily. “Zelensky will probably have to resort to a referendum, I don’t think he can reach such painful and important agreements on his own without popular legitimization,” Klitschko said. Any scenario for a peac…