Complex sentence: I want to write this article not simple for that reason, but because he was, in fact, an influential figure in Cincinnati for five decades--not only politically, but because his opinions were frequently sought on issues of public interest.
Split into simpler sentences: I want to write this article not simple for that reason, but because he was, in fact, an influential figure in Cincinnati for five decades. Not only politically, but because his opinions were frequently sought on issues of public interest.