Due to current events, I went down the rabbit hole of US Constitutional law and found this tidbit: Senator Benjamin Wade was, after the assassination of Abraham Lincoln, next in line to succeed to the presidency had the impeachment of Andrew Johnson passed. According to Wikipedia: I have neither the historical skills nor the patience to attempt an alternate history with this as the turning point. Nor do I have Harry Turtledove's email address. But somebody could knock this one out of the park.
The song remains the same. The reptilian brain vs the educated one. The latter being the one who generally attempts to think up ways to help the big dumb beast evolution along its way.