Origin of blood quantum law
In 1705 the Colony of Virginia adopted the "Indian Blood law" that limited civil rights of Native Americans and persons of one-half or more Native American ancestry. This also had the effect of regulating who would be classified as Native American. In the 19th and 20th centuries, the US government believed tribal members had to be defined, for the purposes of federal benefits or annuities paid under treaties resulting from land cessions.
Native American tribes did not use blood quantum law until the government introduced the Indian Reorganization Act of 1934, instead determining tribal status on the basis of kinship, lineage and family ties. Some tribes, such as the Navajo Nation, did not adopt the type of written constitution suggested in that law until the 1950s. Given intermarriage among tribes, particularly those that are closely related and have settled near each other, critics object to the federal requirement that individuals identify as belonging to only one tribe when defining blood quantum. They believe this reduces an individual's valid membership in more than one tribe, as well as costing some persons their qualification as Native American because of having ancestry from more than one tribe but not 1/4 or more from one tribe. Overall, the numbers of registered members of many Native American tribes have been reduced because of tribal laws that define and limit the definition of acceptable blood quantum.
"The U.S. census decennial enumerations indicate a Native American population growth for the United States that has been nearly continuous since 1900 (except for an influenza epidemic in 1918 that caused serious losses), to 1.42 million by 1980 and to over 1.9 million by 1990." In the 2000 census, there were 2.5 million American Indians. Since 1960, people may self-identify their ancestry on the US Census. Indian activism and a rising interest in Native American history appear to have resulted in more individuals identifying as having Native American ancestry on the census.
Prior to colonization, individual tribes had established their own requirements for membership, including the practice of banishment for those who had committed unforgiveable crimes. Some traditional communities still hold to these pre-contact standards. Tribes that follow lineal descent may require a Native American ancestor who is listed on a prior tribal rations-issue roll, such as the Dawes Rolls for the 'Five Civilized Tribes' in Oklahoma, or a late 19th-century census; in some cases they may also require a certain percentage of Native American ancestry, and demonstrated residence with a tribe or commitment to the community. Few tribes allow members to claim ancestry in more than one tribe. The Little Traverse Bay Bands of Odawa Indians accept persons of 1/4 Native American ancestry, plus documented descent from an ancestor listed in specific records. In part, this recognizes that the Odawa people historically had a territory on both sides of what is now the border between the US and Canada.
Each federally recognized tribe has established its own criteria for membership. Given the new revenues that many tribes are realizing from gambling casinos and other economic development, or from settlement of 19th-century land claims, some have established more restrictive rules to limit membership.
In 2007 the Cherokee Nation voted in the majority to exclude as members those Cherokee Freedmen who had no documented ancestors on the Cherokee-by-blood list of the Dawes Rolls. However, the Cherokee Supreme Court ruled in 2005 that they were legitimate members of the tribe at that time. After the Civil War, the US required the Cherokee and other Native American tribes that had supported the Confederacy to make new treaties. They also required them to emancipate their slaves, and to give full tribal membership to those freedmen who wanted to stay in tribal territory. The Cherokee Freedmen often had intermarried and some had Cherokee ancestry at the time of the Dawes Rolls, qualifying as Cherokee by blood, but registrars typically classified them as Freedmen.
Similarly, in 2000, the Seminole Nation of Oklahoma attempted to exclude two bands of Seminole Freedmen from membership to avoid including them in settlement of land claims in Florida, where Seminole Freedmen had also owned land taken by the US government.
Since 1942, the Seminole have at times tried to exclude Black Seminoles from the tribe. The freedmen were listed separately on the Dawes Rolls and suffered segregation in Oklahoma. More recently, the Seminole refused to share with them the revenues of 20th-century US government settlements of land claims. The Center for Constitutional Rights has filed an amicus brief, taking up the legal case of the Black Seminoles and criticizing some officials of the Bureau of Indian Affairs for collaborating in this discrimination by supporting tribal autonomy in lawsuits. By treaty, after the American Civil War, the Seminole were required to emancipate slaves and provide Black Seminoles with all the rights of full-blood Indian members.
American Indian tribes located on reservations tend to have higher blood quantum requirements for membership than those located off reservation....[reference to table] [O]ver 85 percent of tribes requiring more than a one-quarter blood quantum for membership are reservation based, as compared with less than 64 percent of those having no minimum requirement. Tribes on reservations have seemingly been able to maintain exclusive membership by setting higher blood quanta, since the reservation location has generally served to isolate the tribe from non-Indians and intermarriage with them.