Kovner joined the Haganah in December 1947, and soon after Israel declared independence in May 1948 he became a captain in the Givati Brigade of the IDF.[20] During the 1948 Arab–Israeli War he became known for his "battle pages", headed "Death to the invaders!", that contained news from the Egyptian front and essays designed to keep up morale.[21] However, the tone of the pages, which called for revenge for the Holocaust and referred to the Egyptian enemy as vipers and dogs, upset many Israeli political and military leaders.[22][23] The leader of HaShomer Hatzair, Meir Ya'ari accused him of spreading "Fascist horror propaganda."[24] His first battle page, entitled "Failure", started a controversy that still continues today when it accused the Nitzanim garrison of cowardice for surrendering to an overwhelming Egyptian force.[25][26][27]