"We don't do this with any other group of people," says Jeff Corntassel, a Virginia Tech professor who has written about the politics of American Indian identity. "The idea is to prevent the existence of blond and blue-eyed Indians. And at the same time, there's always been diversity in Indian nations."
The idea that "blood is equated with culture" and that blood can be used to determine national identity is "a 19th century, European idea," Corntassel says.
Most of the tribal rolls used to determine blood quantum were compiled, like the one for the Flathead Reservation, about 100 to 150 years ago. The Indian agents performing the count operated under the same archaic assumptions about biology and culture that produced now-discredited fields such as eugenics and phrenology.
To verify Indian-ness, the federal agents devised degrading "tests": In the 1908 census of the Chippewa, counters plucked hair strands from people to compare to a chart for straightness, and rubbed stomachs. "If your belly turned a brighter red, you would be less Indian," Corntassel says.
Given blood quantum's long and ugly history, not everyone on the Flathead Reservation feels comfortable taking sides in the debate.
"I can't say one way or another if it's good or bad," said Alan Chauncey Beaverhead. "My wife and I, we try to keep to ourselves on this."
Ask Beaverhead what he "is" and he'll answer: "I'm part Kootenai, part Pend d'Oreille, half Yakima, with some Nez Perce and Cree thrown in." All of those relatives add up to an official blood quantum of 57/64. His mixed heritage has caused him some problems -- like the arguments that break out when he plays stickball, a traditional Indian game, with people on the Pend d'Oreille end of the reservation.
"Things will get heated up, and some guy will say, `He's one of those Kootenais. That's how they are.'"
At 39, Beaverhead is one of the youngest people who can speak Salish fluently. He works to keep traditions alive by transcribing folk tales and reminiscences tape-recorded by tribal elders. "Sometimes I think that if we'd kept our language stronger, we wouldn't be having these disagreements."
Darryl Dupuis, a leader in the movement to ease the blood rules, traces his ancestry to his great-grandfather, Camille Dupuis, a French fur trapper who married an Indian, Philomene Finley. Both are listed on the 1904 census, Camille as "white, adopted" into the tribe, and Philomene as "three-fourths Pend d'Oreille."
Look at the modern-day Dupuis, a tall man of 66, and the American Indian features are unmistakable: When he joined the Army in the 1950s, he endured taunts of "Hey, big chief!" But Dupuis' official blood quantum level is just 11/32. And his children are 11/64, which is 5/64 short of the degree required for membership.
"Even if you look like you're an Indian individual and you speak the language and practice the traditions, if you don't have the correct degree of Salish and Kootenai blood, then you can't be a tribal member," Dupuis says.
Still, after 125 years in which his family has intermarried with whites, Dupuis is also clearly a "metis." His is not the classic profile captured in turn-of-the-century studio photographs of tribal chiefs, men of chiseled features and weathered, dark-brown skin.
The differences may be subtle, but to people on the reservation, they are noticeable and important -- if not always spoken. People who are "more Indian" pride themselves on growing up in the old ways. Before meals, they say grace in Salish or Kootenai. They live in corners of the reservation known as "Indiantown" -- whites actually make up a majority of the population here -- or in small trailers along the highways that wind through valleys of yellow grass.