Nigeria poses one of the globe's greatest challenges and risks. It is Africa's most populous country and a major exporter of oil and, potentially, of natural gas, but it's people's efforts to realize their potential have been frustrated by internal conflicts and misrule. The country was nearly torn apart by a secession movement and civil war during 1967-70. Recent crises, set off by the annulment of the June 12, 1993 presidential election, once again...