(Corrects spelling of parliament speaker's first name to Nabih in paragraph 3) * Syrian conflict fuelling political rivalries in Leba**n * Country struggling with violence and eco**mic decline * Parliament postpones vote on president to July 23 BEIRUT, July 2 (Reuters) - Lebanese lawmakers failed to elect a president on Wednesday, for the eighth time, to succeed Michel Suleiman whose term ended in May, prolonging a political vacuum as the country struggles with violence, eco**mic decline and an influx of Syrian refugees. The civil war in neighbouring Syria has aggravated long-standing rivalries in Leba**n, where political power is divided among religious communities - the presidency goes to a Maronite Christian, the parliament speaker is a Shi'ite Muslim and the prime minister a Sunni.