At a time when the socialist movement grouped itself around the Zimmerwald Movement and called for Romania to stay out of the World War, Mille became instead a vocal supporter of joining the Entente Powers, insisting that Romania should assist France and take over Transylvania. In a 1915 letter to Leon Trotsky, the influential socialist and Zimmerwald partisan Christian Rakovsky accused Mille of having been corrupted by Take Ionescu, and of using his newspapers for propaganda "under the mask of independence". He also claimed: "[Ionescu] thus compensated for the weakness of his party, both in men and ideas, through corrupting the press".