I read an article on vice that I thought was pretty sad about how dozens of species have gone extinct while the government decides whether or not to give them protected under the endangered species act. Here are some examples:
the Amak Song Sparrow
the Breckenridge Slender Salamander
the Fresno Kangaroo Rat
the Tacoma Pocket Gopher
the Florida Rainbow Snake
According to the article; 10 species weren't named endangered until after they were found extinct, 42 that went extinct while being considered, and 32 species that went extinct without ever being considered to be listed as endangered.
If there's ample scientific that a species is dying, the law says that measures must be made to protect it. Unfortunately, granting species protection can often be politically controversial primarily because it can halt or slow real estate development and industrial operations. Concerned businesses, and therefore politicians as well, often protest potential listings that they fear will infringe on their economic growth.