Every day the forest elephants convened at Dzanga Bai to drink the mineral-rich waters. Their gathering in this clearing—located in a UNESCO World Heritage site in the Central African Republic—was so reliable that researchers and tourists flocked there for guaranteed sightings of these elusive cousins of the larger savanna elephants. Then, on May 6, poachers from Sudan arrived. They gunned down at least 26 of the animals, hacked off their valuable tusks and left the bodies to rot.

Such events, often carried out by heavily armed militias equipped with helicopters and night-vision goggles, are becoming increasingly common across sub-Saharan Africa. Transnational criminal syndicates run these operations. Profits are high: a kilogram of elephant ivory can fetch $2,000 on the black market; the same amount of rhinoceros horn can command $65,000—more than cocaine or platinum. All told, illegal wildlife trafficking is an estimated $19-billion-a-year industry, which makes it the fourth most lucrative illicit activity in the world after the drug trade, counterfeiting and human trafficking.

That money is bankrolling extremists, terrorists and other criminal groups around the globe. The Somali militant Islamist group and al Qaeda affiliate al Shabaab—which claimed responsibility for the September terrorist attack at the Westgate Mall in Nairobi—generates up to 40 percent of its funding from illegal ivory, according to a 2012 report from the Elephant Action League, an advocacy group based in Los Angeles. Other al Qaeda affiliates, as well as rebel groups such as the Lord's Resistance Army in Uganda, are also said to run on profits from illegal wildlife trafficking. As a result, elephant and rhino poaching has surged to record levels.

The U.S. is taking notice. In July it established a presidential task force on wildlife crime and pledged $10 million in training and technical assistance to combat poaching in Africa. Yet some U.S. policies continue to contribute to the trade. They must end.

The U.S. is the second-largest market for ivory, among other illegal wildlife products, thanks in part to legal loopholes that allow the trade of ivory depending on how old it is and what kind of elephant it comes from. Because it is practically impossible to distinguish old ivory from new and African ivory from Asian, however, criminals can exploit the legal market to launder illegal ivory. The U.S. should ban the trade of all ivory.

It should also stop issuing import permits for hunting trophies of imperiled species. In March the U.S. Fish and Wildlife Service allowed a wealthy American businessman to import a black rhino that he had hunted for sport in Namibia in 2009—the first such permit in 33 years. Black rhinos are critically endangered, with fewer than 5,000 left in the wild. By giving such permits, the U.S. props up rhino horn as a status symbol.

In addition, we need to leverage our investment power abroad. The U.S. should preferentially give foreign aid to those countries that have demonstrated a commitment to protecting wildlife.

Ultimately combating the trade will take equipment and highly trained wildlife rangers, customs officers and investigators, and those resources require money. The U.S. must give far more aid than the $10 million the Obama administration committed in July or even the $80 million a partnership under the Clinton Global Initiative promised in September. Zimbabwe alone recently said it would need a minimum of $40 million to protect its own wildlife.

Most important, the U.S. must endeavor to eliminate the soaring demand for illegal wildlife from Asian consumers, particularly China's burgeoning middle class. We need to work with China and other countries to educate the public: many Chinese buyers think elephants shed their tusks naturally; Vietnamese buyers think rhino horn cures hangovers and cancer. And if necessary, we should shame these countries and institute trade sanctions until they curb consumption. To be sure, these are drastic measures. But we find ourselves in truly desperate times. The fate of these threatened species is tied to our own.