Until recently, Ms. Davis held an honored place on the tribal council, a position that made her the equivalent of a senator in the Seminole Nation. Two years ago, however, a reactionary faction seized control of the tribe and used a legally questionable vote to declare that Ms. Davis, and about 1,500 others, had too little "Seminole blood" to be counted as full tribal members.

The real problem is that Ms. Davis is black, in a tribe that is struggling mightily to distance itself from a history in which black Seminole warriors and chiefs had starring roles. The question of whether the tribe can legally deny federal money to the black Seminole will be decided in a closely watched federal lawsuit known as Sylvia Davis vs. the United States. The case has a deeper significance for historians, who see yet another example of how the American multicultural past is papered over by the myth of racial and ethnic purity.

Modern Americans are typically surprised to learn that Native American tribes had any black members. In most cases, as in several other tribes moved to Oklahoma, black members began as slaves. But even though blacks in the Seminole tribe sometimes posed as slaves to avoid capture, they were in fact full tribal citizens from the very beginning.

The Seminoles did not exist when Europeans colonized the United States. The anthropologist Joseph Opala argues that they are not a Native American tribe at all, but "an Afro-Indian tribe" that coalesced in the mid-1700's when refugees from other tribes came together in the Florida wilderness with runaway slaves from the lower South. The origins of the tribe are suggested in the name Seminole, which has been translated as "runaway," "separatist" or "pioneer."

The Seminole Wars were costly for the American government, both in terms of money and lost lives. Gen. Thomas Sidney Jesup called it "a Negro war . . . not an Indian war," and he warned that it would eventually spread throughout the slave states if the warrior bands were not put down. Ms. Davis's hero, Chief Billy Bowlegs, fought off not just the Army but also the Native American tribes that sought to capture black Seminoles and sell them into slavery. Bowlegs was the last of the major war chiefs at large in Florida, fighting with a band of warriors and dozens of escaped slaves under his protection.

In Oklahoma, where the Seminoles were settled, the residents — black, white and Indian — often lived, worked and were buried together until the advent of statehood. Then the new State Constitution mandated radical segregation in the previously integrated Seminole society. All the Oklahoma tribes were divided into "freedmen" and "blood Indians." This is a questionable distinction in most tribes but a clear violation of history for the Seminoles, who were multiracial from the beginning.

The so-called freedman were given land when the reservations were broken up, but they enjoyed fewer protections under the law. The second-class citizenship worsened over time, becoming an issue in 1991 when Congress voted to compensate the tribe for the lands it lost when it was relocated from Florida.

Sylvia Davis was still a member of the tribal council when she applied for $125 of the federal money to buy clothing for her son, who was starting school. In denying the request, tribal authorities repeated the century-old slander, suggesting that Ms. Davis and her son lacked sufficient "Seminole blood" to be eligible for the money. A similar fate has befallen aging and disabled black Seminoles who have been denied medical care and other benefits that nonblack Seminoles receive freely. When Ms. Davis protested the exclusion of blacks, she said, one local official told her that the black Seminoles needed to "go back to Africa."

The prejudice against black Seminoles can be partly explained by tribal self-hatred and ignorance of history. But court documents filed in connection with the federal lawsuit show that at least one local official in the Bureau of Indian Affairs may have conspired with tribal leaders to hide the exclusion of blacks from Congress, which was bound by treaty to regard black Seminoles as members of the tribe when it voted to pay the Seminoles for Florida.

Federal courts will decide whether the Seminoles' treatment of their black brethren is legal. But the court of public opinion will find it mean-spirited and immoral.