The most sharply contested election in Nigeria ’s post-independence history wound down to a tense conclusion on Saturday amid fears that a polarized electorate would clash regardless of the outcome in a country split on religious, ethnic and sectional lines. There appeared to be little middle ground between partisans of the incumbent president, Goodluck Jonathan , a Christian from the south hated in the north for mismanaging a bloody Islamist insurgency at steep cost, and his challenger, Muhammadu Buhari, a former military ruler, a northerner and a belated democratic convert whose Muslim faith and authoritarian past are feared in the south. Voters on Saturday morning crowded around registration stations here in the north’s largest city, a packed metropolis of more than five million, as hitches in the process added to the tension. Election officials were more than two hours late in some places, and malfunctioning electronic […]