The New England Historic Genealogical Society backtracked on Warren's ancestry in a statement Tuesday, saying the group has "no proof that Elizabeth Warren's great-great-great-grandmother O.C. Sarah Smith either is or is not of Cherokee descent" and that the Society "has not expressed a position on whether Mrs. Warren has Native American ancestry, nor do we possess any primary sources to prove that she is."

The Boston Globe, which had taken the Society's earlier statements as confirmation of Warren's Cherokee heritage ("Document ties Warren kin to Cherokees"), issued a sniffy correction Tuesday about the "1894 document that was purported to list Elizabeth Warren's great-great-great grandmother as a Cherokee," noting that "Neither the society nor the Globe has seen the primary document, whose existence has not been proven."

But even were such a document to be found, Warren would not be eligible to enroll as a Cherokee based on it alone. To begin with, the Cherokee Nation doesn't accept marriage licenses as documentation of Cherokee ancestry -- let alone a document described as an application for a marriage license by a descendent of the individual claimed as Cherokee.

"Marriage licenses don't cut it," said Krehbiel-Burton of the Cherokee Nation.

Further, to enroll as a member of the Cherokee Nation, an individual must have had a direct ancestor listed among the more than 101,000 people enrolled on the "Final Rolls of the Citizens and Freedmen of the Five Civilized Tribes in Indian Territory" between 1898-1914, now known as the Dawes Rolls. The Cherokee Nation is very strict about this, even keeping descendants of siblings of men and women on the rolls out of the tribe, as well as descendents of Cherokees who were living out of the area at the time the lists were drawn up in what was then Northeastern Oklahoma.

"If she does not have an ancestor listed on the Dawes Rolls, she cannot be considered Cherokee through this tribe," explained Lydia Neal, a processor with the registrar's office of the Cherokee Nation.

O.C. Sarah Smith died long before the rolls were drawn up, too far in the past to make Warren eligible for membership in the tribe (assuming Smith was Cherokee).

No direct-line relatives of Warren are listed on the Dawes Rolls, according to Megan Smolenyak Smolenyak (the doubled name is not a typo), the independent genealogist who identified Michelle Obama's slave ancestors in 2009 in a project with The New York Times.

"The Dawes Rolls don't lend support to [Warren's] claim," she told The Atlantic.

The Eastern Band of the Cherokee, for their part, have since 1963 required individuals to be at least 1/16 Cherokee to enroll -- and also to have "a direct lineal ancestor" on "the 1924 Baker Roll of the Eastern Band of Cherokee Indians." Even were Smith discovered to be Cherokee, Warren would not be eligible to join the tribe as someone who also lacks a direct-line ancestor on the 1924 rolls, according to Smolenyak's research.