"It is only prejudice against the negro which calls every one, however nearly connected with the white race, and however remotely connected with the negro race, a negro. The motive is not a desire to elevate the negro, but to humiliate and degrade those of mixed blood; not a desire to bring the negro up, but to cast the mulatto and the quadroon down by forcing him below an arbitrary and hated color line."
January 1, 1970
https://en.wikiquote.org/wiki/Frederick_Douglass