The discovery of an endangered species on the site where a hospital was being built in San Bernardino County, California, forced the builders to relocate the hospital at a cost to taxpayers of about $4.5 million. The species responsible for this expensive relocation was the Delhi sands fly, one of over thirty insects protected by the Endangered Species Act (ESA). ESA regulations allow the federal government to restrict activities such as farming or logging that might harm the organism or its habitat, even if the threatened species is on private land.

Many private landowners claim that ESA restrictions on their property result in lost revenue. For example, Ben Cone of North Carolina contends that he lost $1.5 million when the federal government found endangered red-cockaded woodpeckers on his land and prohibited him from harvesting timber on it. Opponents...