The Wyoming, Montana, and Idaho Farm Bureaus (joined by the Audubon Society) brought suit against the Department of Interior for violating the provisions of the Endangered Species Act by introducing Canadian wolves into an area where indigenous wolves already existed. The U.S. District Court held for the Farm Bureaus and the National Audubon Society and ordered that the reintroduced gray wolves and their offspring be removed from Yellowstone and Idaho. According to the District Court, because the reintroduced wolves are part of an experimental population, the Endangered Species Act permits residents of the area to shoot wolves found preying on livestock. Native wolves, however, would also be in danger of being shot, in violation of the Endangered Species Act. The judge therefore held that the reintroduction plan was illegal. In January 2000, the 10th U.S. Circuit Court of Appeals overturned the decision of the lower court, and the Farm Bureau decided not to appeal the decision to the Supreme Court.

More than 10 years after the reintroduction, the wolf population at Yellowstone is thriving. Researchers are beginning to see that the wolves’ reintroduction is slowly changing the balance of the park ecosystem: elk no longer wander in the open, for example, and the dominance of the coyote has been challenged. However, in other areas of the country, wolf reintroduction has not been as successful and wolves remain endangered in most of the U.S. Debate continues about their reintroduction. Ultimately, the controversy among environmentalists, ranchers, and other stakeholders remains the same: is there a plan that is both economically and ecologically beneficial?