Nigeria, July 13 -- Three score and three years ago, a defining dispute erupted in the old Western Region of Nigeria over the scope and reach of constitutional conventions in determining or terminating the tenure of high-level political leadership. The Judicial Committee of the Privy Council, which ultimately had to pronounce on the matter, described conventions in that case as "a body of understandings which no writer can formulate." The aftermath of that decision took the country to the brink of ruin.

This year, the Nigerian Bar Association (NBA) confronts its own moment of truth concerning how far conventions initially designed to accommodate national diversity in its leadership processes can be converted into ethno-tribal vetoes by e...