Signed in to law on December 28, 1973 by President Richard Nixon. Under the ESA, the federal government has the responsibility to protect: Endangered Species - species that are likely to become extinct throughout all or a large portion of their range. Threatened Species - species that are likely to become endangered in the near future. Critical habitat - vital to the survival of endangered or threatened species.

The law disallows the hunting or taking of any endangered species. It also prohibits the destruction of habitat inhabited by endangered species. Any action that adversely affects an endangered plant or animal’s habitat is outlawed.  The law also prohibits any action that causes a "taking" of any listed species of endangered fish or wildlife. Likewise, import, export, interstate, and foreign commerce of listed species are all generally prohibited.

The Fish and Wildlife Service and National Oceanic and Atmospheric Administration enforces the Endangered Species Act. The Environmental Protection Agency also is responsible for protecting endangered species. For instance, the EPA may prohibit the use of a pesticide that adversely affects the habitat of an endangered species.