James A. Mackay was a decorated World War II veteran, who returned to Georgia in 1945, determined to make a difference in the segregated world of Georgia politics. He was a staunch opponent of Georgia’s county unit system that entrenched political power in rural counties. From 1950 through 1964 he was a state house member who fought to keep Georgia public schools open in the face of political opposition to desegregation. Elected to Congress in 1964, he was one of two deep-South congressmen who voted in favor of the 1965 Voting Rights Act. In 1967 he co-founded the Georgia Conservancy. For the next 25 years he was Georgia’s leading environmentalist. This thesis explores Mackay’s life from 1919-1950 and the significance of his parents, his experiences at Emory University, World War II, his legal challenge to the county unit system, and his role in writing Who Runs Georgia?