Over the course of a 25-year career, Stuart Mellan, former CEO of the Jewish Federation of Southern Arizona, could see that his organization was losing relevance. By the federation’s main metric, he had been a successful leader. From 1995 until 2020, when Mellan retired, federation annual campaigns more than doubled from $2 million in unrestricted funds to $4.5 million, of which almost a third were donor-directed funds. But there was another, much larger game in town: During the same period, assets of the Jewish Community Foundation of Southern Arizona soared from $12 million to $108 million. Soon, he saw, the...