some. reporter: brownlee s world view has evolved dramatically since then. the self-described pragmatic progressive was recently informed that several generations ago her forbearers were slave holders. on the one hand, i wasn t too surprised. on the other hand, when they said your great, great grandfather had two slaves and a child slave, that really hit me really hard. it hit me very, very hard. reporter: through public documents and family records, a reuters examination discovered at least 100 members of the last sitting congress had direct family ancestors who were slave holders. more than a quarter of republicans, 8% democrats. so too every living american president except donald trump. when you learned that, did it surprise you? not at all. power is something that s often