Warren led the trial team representing seven suburban school districts in the Milwaukee desegregation case. As part of that case, he was also a leading negotiator in the settlement proposal which later served as a blueprint for the settlement which was approved by the Court.
Warren participates on a regional and national level in school law matters.
He served as a director of the National Council of School Attorneys which is affiliated with the National School Boards Association. At the state level, he was a board member and served as president of the Wisconsin School Attorneys Association. His work was recognized when the Wisconsin School Attorneys Association awarded him the George Tippler Award for distinguished service in school law.