Ever since the Commission on Presidential Debates was formed in 1987, it has been co-chaired by a past chair of the Republican National Committee, and a past chair of the Democratic National Committee. However, with no public announcement, recently Michael McCurry, the co-chair who had earlier been Democratic National Committee chair, resigned.

He was replaced with Dorothy Ridings, who was president of the League of Women Voters thirty years ago. This article at presidentialdebatenews.com has more details. The article also says many directors of the CPD have resigned in the last few months. Thanks to Independent Voters Network for the link.