National Parks are the sacrificed land that gets people interested in preserving public land. It's much easier to get national support to "Save Yellowstone" than to get people to care about saving Bridger-Teton National Forrest. However, the policies that benefit one often benefit the other.
Let as many people in to Yellowstone as possible so that they can look back on that one trip through Wyoming and feel like they have a personal interest in saving our public lands.