Dividing Western Waters: Mark Wilmer and Arizona V California

By the time Mark Wilmer settled in the Salt River Valley in the early 1930s, he realized that four basic commodities made possible civilization in the arid West: land, air, sunshine, and water. For Arizona, the seminal water case, Arizona v California, the longest Supreme Court case in American history (1952-1963), constituted an important step in the construction of the Central Arizona Project (CAP), a plan crucial for the development of Arizona's economic livelihood. The unique qualities of water framed Wilmer's role in the history of the arid Southwest and defined his towering professional career. Wilmer's analysis of the Supreme Court case caused him to change legal tactics and, in so doing, he changed the course of the history of the American West.