This is a really cool TL! Any hints as to the outside world or just focusing on the Union?
I've mostly been focusing on the Union, aside from a few abstract thoughts I've had on the rest of the world. I'm open to some suggestions.
I have been toying with one idea which is that the ideology that the Union is founded on is a warped one, loosely inspired by Cromwell's failed Commonwealth. It's pushed by an TTL author and founding father named Isaac Fox, who writes a series of political pamphlets, manuscripts and novellas prior to and during TTL's war of independence. Essentially, Cromwell and his supporters are exiled to Saybrook.