Corraled in a federal holding pen at Palomino Valley, Nev., a buckskin mare with the number 9598 cold-branded in code on its neck suddenly faces an uncertain future. When the 12-year-old was rounded up in November as part of a federal program to humanely control the mustang population in the West, it looked as if it would be relocated to a grassy farm in Oklahoma or Kansas. But that all changed weeks later. Thanks to a controversial revision of the 1971 law protecting wild horses and burros, the mare could be sold, killed and butchered.

Icons of independence and a living reminder of the old West, mustangs have always excited fierce passions. But the passion turned to anger after Republican Sen. Conrad Burns of Montana quietly inserted a rider in the federal budget that lifted the ban on selling wild horses for slaughter. The revision forces the Bureau of Land Management (BLM) to sell "without limitation" every captured horse that is 10 or older or has proved unadoptable. The new rule applies to 8,400 horses in captivity, and many more in the future. "This consigns thousands of horses to death," says Howard Crystal, a lawyer for the Humane Society. Last week Democratic Rep. Nick Rahall of West Virginia introduced a bill to restore the old protections. "When Americans picture the West, I doubt they envision wild horses' being rounded up and sent to slaughterhouses to be processed into cuisine for foreign gourmets," says Rahall.

About 50,000 domestic horses are killed every year at three U.S. slaughterhouses, mostly to be shipped to France and other countries where horse meat is socially acceptable food. A bill that would ban the slaughter of any horse in the United States for human consumption will be introduced in Congress this week.

The mustangs' current troubles come thanks in part to another Western icon: cattle ranchers. There are currently 37,000 mustangs sharing public rangelands with several million head of cattle. The result has been overgrazing, exacerbated by six years of drought. To restore the land, the BLM has cut the number of cattle allowed, and ranchers say the horses and burros have to be pared substantially. "If we don't receive relief, and soon, we'll be out of business," Lemoille, Nev., rancher Kenneth Jones told a state legislative committee last summer. The BLM wants to cut the horses and burros on the range by 9,000 to 28,000, but critics of the agency complain that horses are being blamed for damage caused by the more-numerous cattle. "It's not the 37,000 horses that are tearing up the land," says Chris Heyde, an analyst with the Society for Animal Protective Legislation.

Horse advocates complain that Senator Burns came up with the worst possible fix. "What's so senseless about this is that humane alternatives exist," says Rahall. He suggests controlling the populations by gelding the stallions; others are pushing to expand a pilot program in Nevada that injects mares with a long-term contraceptive. Nearly everyone wants to improve the existing adoption program that has put thousands of horses in private hands.

Nobody can predict how many horses will wind up in slaughterhouses. Burns believes "most of these horses" won't, because sales (expected to begin later this year) will be simpler than adoptions. In the meantime, the BLM is talking to private horse sanctuaries in hopes they will take some of the animals. Neda DeMayo, who runs a nonprofit 220-horse sanctuary in Lompoc, Calif., promises she and other advocates will save as many as they can afford to, but "we can't save them all." Montana rancher Merle Edsall hopes the new rules will finally enable him to build a tourist attraction in northern Mexico featuring thousands of American mustangs. That may not sound like the most surefire solution, but as slaughter looms, a lot of ideas may start to look better.