Former Nigerian Leader Obasanjo Backs Abubakar for PresidentObasanjo, an influential politician and former military ruler of Africa’s top oil producer, decided to support Abubakar “because the alternative is unthinkable,” he said Thursday by phone from the southwestern city of Abeokuta, where the two men met earlier in the day. “Politically it is a significant endorsement for Atiku,” Clement Nwankwo, executive director of the Abuja-based Policy and Legal Advocacy Centre, said by phone. Abubakar, 71, easily won the presidential nomination of the opposition Peoples Democratic Party on Oct. 7.