endangered species act

“The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species.
Scientists would like to have a list of all the species on Earth. That sounds like a relatively straightforward, purely academic exercise, but it really isn't. Unfortunately, one major reason is politics.
Every so often, the world debates whether or not it should exterminate the only known samples of smallpox. So far, we always have decided to keep them around, just in case we need them for research or vaccine development.