On Dec. 8, 1969, the sixth Illinois Constitutional Convention opened in Springfield. Almost a century had passed since Dec. 13, 1869, when the fourth Illinois Constitutional Convention opened. That convention had drafted the constitution that the new delegates were hoping to revise.One issue dominated both conventions: How to write a basic charter for a state that often seemed split into two competing parts. The commercial Northeast often seemed unrelated to the vast and verdant prairies of downstate Illinois.When Gov …