John Muir was a nature writer and a preservationist who also started the Sierra Club. He stated that they should preserve the valley because it was a spiritual and aesthetic resource for the public. He was the main opponent of the debate. The majority of the debate occurred between him and Gifford Pinchot. After he lost in the debate, he was heartbroken and passed away a year later. Many national monuments and parks have been named or built in his honor.
John Muir relaxing in the wilderness source: PBS Organization