Historically anyone who became President was subject to any imaginary calumny his opponents and enemies could dream up, and it was very common for these to include insults concerning genealogy. Such insults were often dreamed up out of whole cloth and circulated to impress those who were mindless enough to care about racial lineage rather than merit in the present.

The point is that being able to find a letter or other paper accusing someone of having alien blood in his veins is no guarantee whatsoever that such a proposition has any more merit than a gnat;s fart in a hurricane.

Furthermore, the fact that people were racist as all get-out two hundred years ago has no bearing on the ugliness of racism in today's world. Past racism does not modify current racism, except to show the breeding from which it is inherited, a half-wit sad-sack dim-bulb sort of legacy and nothing to be proud or arrogant about.