Headlines tend to focus on the other Yellowstone controversy: The prolonged legal battle that pits snowmobile-driving tourists and the businesses that rely on them against environmentalists fighting for wildlife, air purity and tranquility.

On Sylvan Pass, though, the stakes are higher. And the rangers are compelled to risk their lives not solely by the need to allow visitors to access the park, but also by the complex relationship that Wyoming has with Yellowstone. Though 96 percent of the park lies within the state's borders, Wyoming gets less than half of the park's annual tourist traffic. That leads many people in the state to feel both possessive about the park and yet somehow slighted.

Sylvan Pass has never handled more than about 5,000 tourist trips a winter, about 5 percent of the park's total snow-vehicle traffic. And the nine years of lawsuits over parkwide snowmobile traffic have caused the flow to decline, due to the tangle of judges' rulings and policy shifts. By 2007, the pass's winter traffic had dwindled to a few hundred tourists, and some businesses dependent on the traffic closed down.

Meanwhile, park bosses have explored the possibility of closing the pass all winter, and in a 2007 final environmental impact statement, they announced that the pass would be closed beginning in the 2008-09 winter.

But the interests determined to keep Sylvan Pass open were stronger than they appeared. The park's move instantly drew opposition from Cody, Wyo. -- the first real town on the two-lane highway downhill from the east gate. It's 52 miles away and has only 9,000 residents, but it retains the spirit of its founder, Buffalo Bill Cody -- a pioneer promoter of tourism, who staged Wild West shows around the world a century ago. On its Web site, the Cody Country Chamber of Commerce proudly calls the town "The Preferred Gateway to Yellowstone National Park."

The local newspaper, the Cody Enterprise, whose logo boasts that it was also founded by Buffalo Bill, fired off editorials charging that the Park Service exaggerated the downsides of avalanche control. It denounced the agency's plan as "punitive … obstructive … unprofessional … prejudiced … (using) bogus assumptions and manipulated material … a thoroughly dishonest effort … a real laugher were it not so serious for northwest Wyoming." One editorial warned that "the careers of some of those NPS officials closest to this scandal will suffer."

A grassroots group called Shut Out of Yellowstone sprang up, led by two well-connected Republican women, Carol Armstrong and Tonia Grdina; their party runs the local government and most of Wyoming. "The winter economy is so much more fragile," says Grdina. "It's very important to retain (park access) and build as large a tourist base as we can." More than 500 locals showed up for the group's biggest meeting, in the Cody Community Center auditorium in March 2007, where many vented their anger.

Cody's representatives in the Wyoming Legislature, including influential Rep. Colin Simpson -- son of popular retired U.S. Sen. Alan Simpson -- joined the fray. Colin Simpson, now the speaker of Wyoming's House of Representatives, led the Legislature to pass a unanimous resolution calling for the park to keep Sylvan Pass open. The whole state seemed officially unified; Democratic Gov. Dave Freudenthal took the same stand, as did the entire congressional delegation. And they had the ear of the highest Wyomingite in the Bush administration, Vice President Dick Cheney. They told the Park Service: You'd better think twice about giving Wyoming the shaft.

The Park Service was armed with technical reports from avalanche experts, who said the paramount goal should be to "avoid negative avalanche-human contact," meaning to avoid having people killed by snow. But faced with political pressure, the agency blinked. It agreed to reconsider its decision by going through a process that appeared rigged. The so-called Sylvan Pass Study Group consisted of at least seven advocates for keeping the pass open, including Rep. Simpson and local politicians, and only two park representatives, including Superintendent Suzanne Lewis. They met repeatedly during 2007 and 2008. Often, no members of the public were allowed in.