The Sierra Club supported Theodore Roosevelt's policy of creating national parks because they were of the opinion that natural resourses needed to be preserved for the future generation. The Sierra Club's main goal was to protect and explore the natural resources and wild places on the earth. They had set a target to promote the responsible usage of all the natural resources that are present in the earth. This club also had the mission to educate people regarding the importance of protecting the natural resources. This is why this club supported Roosevelt's policy of creating national parks.