In 2008 for a story for Harper's magazine, journalist Christopher Ketcham stalked the snowy, pine-filled landscape on the Montana-Wyoming border in Yellowstone National Park with a group of environmental activists known as the Buffalo Field Campaign.

For decades, volunteers for the group had filmed men working on behalf of the West's powerful agribusiness industry as they ran down and killed bison that tried to migrate out of the park.

But this year, when Ketcham and the campaign asked for unrestricted access to a corral just inside the northwestern corner of Yellowstone where park employees pen hundreds of buffalo before they are trucked to slaughterhouses, the National Park Service (NPS) said no.

That refusal has sparked outrage among activists beyond those concerned about animal welfare, putting the dispute over the fate of the buffalo into the realm of free speech. Late last week James J. Holman, an attorney working with the American Civil Liberties Union of Wyoming, sent park officials a letter threatening to sue the NPS. Holman's representation of the parties is part of Duane Morris' Pro Bono Program.

"The First Amendment aspect is what got us involved," he said. "The bottom line is this is something that is very important to a lot of people."

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