A sweet book by Daniel Easterman, based on a What if during the Depression we saw the birth of a facist alliance with the figureheads of the KKK, in much the same position as the SA in Germany. In the 1932 electoins, the Aryan Alliance of America presidential candidate Charles Lindbergh beats Roosevelt by a small margin.

By 1940 the USA is a facist state with slavery, ghettos, and concentration camps. A British agent is sent in by sub to assassinate elements in the White House who are pressing for an alliance with the Nazi regime of Germany. He uncovers plans for an American Final Solution and a German/American atomic project.

Point of divergence from our timeline: 1929