Since Nigeria's transition from military to civilian rule in 1999, the country's Supreme Court has risen from a position of relative political obscurity and institutional vulnerability into a prominent and independent adjudicator of inter-governmental disputes in this chronically conflicted federation. Examined here is the Court's arbitration, during President Olusegun Obasanjo's two civilian constitutional terms (1999–2007), of fifteen different federal-state litigations over offshore oil resources, revenue allocation, local governance and public order. The Court's federalism decisions were remarkably independent and reasonably balanced, upholding the constitutional supremacy of the Federal Government in several findings, tilting towards the states in some declarations, and simultaneously underwriting federal authority and state autonomy in other rulings. Despite the Court's important and independent role, however, the Nigerian federation was vexed by violent conflicts, underscoring the structural, political and constitutional constraints on judicial federalism in this notoriously complex and divided country.