JERUSALEM—Isaac Herzog, a veteran politician and the scion of a prominent Israeli family, was elected president Wednesday, a largely ceremonial role that is meant to serve as the nation’s moral compass and promote unity. Herzog is set to become Israel’s 11th president after securing 87 votes in a secret ballot among the 120 members of the Knesset, or parliament. He will succeed Reuven Rivlin, who leaves office next month at the end of a seven-year term. “I intend to be the president of everyone,” Herzog said after the votes were tallied. “We must defend Israel’s international status and its good reputation in the family of nations, fight antisemitism and hatred of Israel, and preserve the pillars of our democracy.” Herzog, 60, is a former head of Israel’s Labor Party and opposition leader who unsuccessfully ran against Prime Minister Benjamin Netanyahu in the 2015 parliamentary elections. He comes from a prominent …