Going back 40 generations, say, a simple counting argument shows that your family tree and mine are not trees. They can’t be, because there weren’t $2^{40}$ people alive then (that’s over a trillion, right?), and never have been. Even four or five generations back, confluence is legal, respectable, and genetically harmless. So the number of your ancestors of a certain generation – or over all time – could well be divisible by 12.

“Ancestry”, as I understand it, is weighted by the number of directed paths involved, and would have to be a binary fraction.

Quibbling about mathematics is more pleasant than contemplating the names of certain sports teams.

We can help. We can push back. Let’s do this!

You might consider adding the Brennan Center for Justice (https://www.brennancenter.org/) to your list of organizations – they do research and advocacy for voting rights (and other things, but I mostly know them from their comprehensive reports about things like how voter ID laws are implemented in practice).

But it *is* possible that “1/12 of my living ancestors from the year 1800 were Cherokee.”

Or even “There were 12 people living in 1800 who were my ancestors, who also did not have any older living ancestors of their own. One of those twelve people was Cherokee.”

This is possible because people have children at different ages. All of my mother’s great-grandparents, plus all of my father’s grandparents could have been born in the same year. That makes twelve.

In this way you can argue for 1/12 Cherokee ancestry without having to approximate binary fractions.