I once seriously annoyed my mother-in-law by arguing Americans are all monarchists, without exception, judging by their national political rhetoric.
Here's a columnist who wants Grant taken off the $50 bill and replaced with Frederick Douglass. "The general was ill-prepared to run the country" you see. Presumably Douglass would have made a more effective Gilded Age imperator. This guy is a history reader, BTW.
Perhaps this is pop culture interpreting, in its own light, the Lincoln Administration and then using it as a standard...
(Hat tip to Russell Bonds who says he hasn't seen a fifty lately.)