The Endangered Species Act was a groundbreaking piece of legislation, vastly improving the first few versions of laws inspired by the plight of the whooping crane (Grus americana).
However, this law is not a guarantee that the species needing protection from extinction will get it. The governmental agencies responsible for listing species often drag their feet, when protecting wildlife will harm interests like timber, grazing, and agriculture.
For the most famous example of how the ESA can be circumvented see the snail darter (Percina tanasi) case, argued by Zyg Plater against the Tennessee Valley Authority. Briefly (from http://www.ti.org/ESAHistory.html):
1978 - The Supreme Court rules that the Endangered Species Act requires that construction of Tellico Dam be halted. The arguments that $78 million had already been spent on the dam or that the endangered snail darter was only a tiny fish do not impress the court. The "plain intent" of the law, say six of the nine members, is to save all species "whatever the cost."
1978 - Congress responds to the court ruling by creating the "god squad": a committee that could exempt selected species from protection.
1979 - The first meeting of the god squad decides, with the Supreme Court, that the snail darter should take precedence over Tellico Dam.
1979 - The Tennessee congressional delegation responds by slipping a rider into an appropriations bill exempting Tellico Dam from the Endangered Species Act. The rider narrowly passes. The Tennessee Valley Authority completes the dam.
The current administration has a disappointing record when it comes to listing the growing number of species in need of protection. Here is an excerpt from the non-profit organization Forest Guardians:
“Under the Bush Administration, the federal endangered species program is faltering. President George W. Bush has made his mark as the only president under whom not one taxon has been listed on the initiative of the administration. All listings under George W. Bush have occurred as the result of court-orders. Only 7-8 species have been listed since George W. Bush has been in office, the lowest under any president since the Endangered Species Act was passed. Contrast this with an average of 65 species per year under Bill Clinton and 59 species per year under George H.W. Bush.”
To participate in advocating for the protection of the Endangered Species Act, follow this link to send a letter to your senators. It only takes a minute and helps give you a voice!