While the outrage grows over the killing of a famed lion by a Minnesota trophy hunter, the United States turns out to be the world's largest importer of African lion trophies from safari hunts with an average of 432 a year.

Between 1999 and 2013, about 5,763 wild-source lions just for hunting trophy purposes, according to the Humane Society of the United States.

Hoping to cut those numbers, the group urged the federal government to list the lion on the endangered species list and, last October, the U.S. Fish and Wildlife Service proposed a rule to list the lions as threatened.

However, it included a loophole that would allow trophy hunters to bring home their kills from countries with lion management programs.

The service said, "The rule, if finalized, will establish a permitting mechanism for the importation of sport-hunted lion trophies, provided that the lions originate from countries with a scientifically sound management plan for African lions. Sport-hunting was not found to be a threat to the species at this time. By providing incentives through the permitting process to countries and individuals who are actively contributing to lion conservation, the Service will be able to leverage a greater level of conservation than may otherwise be available."

Map of African lion ranges. USFWS

Zimbabwe, where the lion named Cecil was killed by an American archer, apparently has a sound management policy. The agency currently only bans the importation of elephants taken as hunting trophies but if it decides that the lion is "threatened," it could ban importation.

To close that loophole, HSUS President Wayne Pacelle said he sent a letter to the fish and wildlife service urging action. On his blog, he wrote:

"Today we sent a letter to the U.S. Fish and Wildlife Service, which recently took steps to protect chimpanzees and African elephants, urging the agency to make final its regulation to upgrade the legal status of lions, to restrict people from trekking to Africa and bringing back their parts for no good reason."

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com.