Lions are endangered, there's no legitimate doubt about that. Requirements for meeting the international definition for endangerment are clear, and if anything, very conservative (look up CITES for more info). The very steep decline in lion population in recent years has been unknown to most Americans in particular, for a simple reason; wealthy special interests based in the U.S. are the primary cause of poaching and killing wild lions, having doubled the number of lion "trophies" imported to the U.S. in less than 10 years. Major wildlife non-profits have been trying to have African lions listed under the ESA because the U.S. is by far the largest market and destination for lion "trophy" parts, and they continue to be blocked by the tiny, very wealthy "trophy" hunting organizations. Listing under the Endangered Species Act would criminalize the importation, effectively ending the reason for the "canned hunts" and poaching. This is considered by wildlife scientists to be the most essential action possible to stop the population decline and save lions from extinction.
Lions are endangered, there's no legitimate doubt about that. Requirements for meeting the international definition for endangerment are clear, and if anything, very conservative. The very steep decline in lion population in recent years has occurred for a horrifyingly simple reason; wealthy special interests, based primarily in the U.S., are the principle cause of poaching and killing wild lions, having doubled the number of lion "trophies" imported to the U.S. in less than 10 years. That figure was (in 2011) parts of at least 3,600 wild African lions. Listing under the Endangered Species Act would prohibit all such importation, effectively ending the reason for the "canned hunts" and poaching, and criminalizing the tiny, but very wealthy, minority responsible. Listing the lion with the ESA is an indispensable step in stopping the dramatic population decline and preventing extinction for African lions.
The plight of the lions is wonderfully shown in the National Geographic film The Last Lions; at the time the film was so titled, just under 2 years ago, there were several thousand more lions in the wild than now. In 2011, as of course you're aware, seven of the world's most respected wildlife non-profits, supported by many more, began petitioning to have the African lion listed as endangered under the ESA. Action to protect the lions is called an emergency requiring urgent action, by wildlife non-profits and scientists, with national legislation against "trophy" importation and canned hunting as the most important action needed; listing lions under the ESA, in accordance with scientific fact, is clearly the easiest and most efficient way to do this. The U.S. is the world's largest importer of African lion parts, and is the clear leader in not only canned hunting, but the profitability of poaching, all to provide "trophies" for a few of the obscenely super-rich. It should be noted that canned hunting is a deliberately deceptive name for a practice held in contempt by normal hunters.
The following figures are from the Humane Society of the United States: Between 1999 and 2008, 7,090 lion trophies were traded internationally by recreational hunters. Most of these trophies (4,139) were imported to the U.S. In the same decade, 2,715 wild-caught lion specimens (i.e., lions and their body parts) were also traded internationally for commercial purposes. The U.S. imported 1,700 of these specimens, or 63 percent. The specimens most often traded commercially were claws, trophies, skins, live animals, skulls, and bodies. All of this is being taken from an endangered species that isn't listed for "political", meaning purely greed-based, reasons, making the possible extinction of African lions a quintessentially American nightmare.
Some Africans survive by breeding lions in small enclosures for "safari hunts", which of course involve no hunting at all, or by killing lions for their body parts, while in contrast, a program in Kenya, Living with Lions, trains Maasai warriors to protect the lions, while others are learning to survive by helping in many ways. The entire African ecology has been dramatically changed and harmed by the loss of lion populations, making the answers on the ground more complex. It has been found consistently and reliably that whenever informed, people living near and with endangered species will rapidly implement change to do as much as they can to help.
There are fewer lions left than the numbers of many species that are listed under the ESA, appropriately, as endangered, down from about half a million within most adults' lifetimes. At an estimated 20,000 now, the lions outnumber some of the other top predators targeted by "trophy" hunters, while experiencing a more rapid decline in population. While it's true that the onerous activities against wild lions do exist in, and can be moved to, other locations, action to protect lions by the U.S. would also demonstrate very powerful leadership for further action and awareness around the world.