But this concept of the powerful subjugating people who are weaker than them did not lose. It was simply reinforced by the Civil War.
The slaves were freed simply because it was advantageous for the conquering power that it be so. They didn't intend to do that when they started, but they became increasingly angry at the people who had defied them, and freeing the slaves was not only revenge, it was just one more means to insure the South would never again become so financially powerful as to threaten the masters of Northern mercantilism again.
And this social/financial elite has been ruling the nation ever since.
By 1945 the Germans were on the ropes.By 1865 so was the Confederacy.