The National Park Service, an agency in the U.S. Department of the Interior, was established by the National Park Service Act of 1916 making it the first such agency in the world. Its mission as stated in the Act is: "to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such a manner and by such means as will leave them unimpaired for the enjoyment of future generations."

The mission has not changed over the years but the ambiguous wording of the act has sparked much debate over what the primary use of a national park should be. Some people feel the parks should be commercially developed in order to best "provide for the enjoyment" of the resources, whereas others think the highest priority should be preserving the resources...