Blackouts have hit West Africa's second-largest economy again, and Ghana's president is blaming saboteurs in Nigeria's distant oil-producing Niger Delta region for the power cuts. Ghana was once one of West Africa's fastest-growing economies, but power shortages, government overspending and drops in the price of its major commodities led to years of slowing growth and a nearly $1 billion IMF bailout. In a speech last week, President John Dramani Mahama blamed recent power...