The reintroduction plan won support, but not without some compromises. Defenders of Wildlife, a private conservation group, promised to compensate ranchers who lost livestock to wolves, and the federal government ruled that ranchers could kill wolves caught attacking their animals.

Both ranchers and environmentalists, who feared that the compromises would put the wolves in danger, challenged the reintroduction in court. A judge agreed with the arguments and ruled the plan illegal. In December 1997 he ordered the wolves’ removal from the park, but stayed the order pending an appeal. And in January 2000 a Denver, Colorado, district court overturned the order, allowing the wolves to stay in Yellowstone.