It's Navajo Nation v. U.S. Forest Service; I haven't yet read the whole opinion (I'm on a trip), but here are the opening paragraphs:
In this case, American Indians ask us to prohibit the federal government from allowing the use of artificial snow for skiing on a portion of a public mountain sacred in their religion. At the heart of their claim is the planned use of recycled wastewater, which contains 0.0001% human waste, to make artificial snow. [Footnote: It appears that some of the Plaintiffs would challenge any means of making artificial snow, even if no recycled wastewater were used.] The Plaintiffs claim the use of such snow on a sacred mountain desecrates the entire mountain, deprecates their religious ceremonies, and injures their religious sensibilities. We are called upon to decide whether this government-approved use of artificial snow on government-owned park land violates the Religious Freedom Restoration Act of 1993 (“RFRA”), 42 U.S.C. §§ 2000bb et seq., the National Environmental Policy Act of 1969 (“NEPA”), 42 U.S.C. §§ 4321 et seq., and the National Historic Preservation Act (“NHPA”), 16 U.S.C. §§ 470 et seq. We hold that it does not, and affirm the district court’s denial of relief on all grounds.
Plaintiff Indian tribes and their members consider the San Francisco Peaks in Northern Arizona to be sacred in their religion. They contend that the use of recycled wastewater to make artificial snow for skiing on the Snowbowl, a ski area that covers approximately one percent of the San Francisco Peaks, will spiritually contaminate the entire mountain and devalue their religious exercises. The district court found the Plaintiffs’ beliefs to be sincere; there is no basis to challenge that finding. The district court also found, however, that there are no plants, springs, natural resources, shrines with religious significance, or religious ceremonies that would be physically affected by the use of such artificial snow. No plants would be destroyed or stunted; no springs polluted; no places of worship made inaccessible, or liturgy modified. The Plaintiffs continue to have virtually unlimited access to the mountain, including the ski area, for religious and cultural purposes. On the mountain, they continue to pray, conduct their religious ceremonies, and collect plants for religious use.
Thus, the sole effect of the artificial snow is on the Plaintiffs’ subjective spiritual experience. That is, the presence of the artificial snow on the Peaks is offensive to the Plaintiffs’ feelings about their religion and will decrease the spiritual fulfillment Plaintiffs get from practicing their religion on the mountain. Nevertheless, a government action that decreases the spirituality, the fervor, or the satisfaction with which a believer practices his religion is not what Congress has labeled a “substantial burden” -- a term of art chosen by Congress to be defined by reference to Supreme Court precedent -- on the free exercise of religion. Where, as here, there is no showing the government has coerced the Plaintiffs to act contrary to their religious beliefs under the threat of sanctions, or conditioned a governmental benefit upon conduct that would violate the Plaintiffs’ religious beliefs, there is no “substantial burden” on the exercise of their religion.
Were it otherwise, any action the federal government were to take, including action on its own land, would be subject to the personalized oversight of millions of citizens. Each citizen would hold an individual veto to prohibit the government action solely because it offends his religious beliefs, sensibilities, or tastes, or fails to satisfy his religious desires. Further, giving one religious sect a veto over the use of public park land would deprive others of the right to use what is, by definition, land that belongs to everyone.
“[W]e are a cosmopolitan nation made up of people of almost every conceivable religious preference.” Braunfeld v. Brown, 366 U.S. 599, 606 (1961). Our nation recognizes and protects the expression of a great range of religious beliefs. Nevertheless, respecting religious credos is one thing; requiring the government to change its conduct to avoid any perceived slight to them is quite another. No matter how much we might wish the government to conform its conduct to our religious preferences, act in ways that do not offend our religious sensibilities, and take no action that decreases our spiritual fulfillment, no government -- let alone a government that presides over a nation with as many religions as the United States of America -- could function were it required to do so. Lyng v. Nw. Indian Cemetery Protective Ass’n, 485 U.S. 439, 452 (1988).