A thought-provoking feat of world-building.

By (apparently) Rebecca Stirling and Richard Collins? Someone get them a proofreader and publisher, STAT.

Predecessors: there hasn’t been much discussion (in detail) of a fictional socialist USA. It’s played for amusement in “Back in the USSA” by Eugene Byrne and Kim Newman, where much of USSR history is mapped onto the USA.

http://www.uchronia.net/label/newmbackin.html
https://www.alternatehistory.com/forum/threads/back-in-the-ussa.196465/
http://tvtropes.org/pmwiki/pmwiki.php/Literature/BackInTheUSSA

https://quantumbranching.deviantart.com/art/Back-In-The-USSA-409464583

Terry Bisson’s Fire On The Mountain utilizes precedents of anti-racist activism in the USA to portray a successful slave rebellion in the American south, changing the political landscape forever.
https://en.wikipedia.org/wiki/Fire_on_the_Mountain_(Bisson_novel)
https://www.goodreads.com/book/show/166902.Fire_on_the_Mountain
https://boingboing.net/2010/07/28/bissons-fire-on-the.html
https://www.alternatehistory.com/forum/threads/does-anyone-here-think-terry-bissons-fire-on-the-mountain-is-plausible.166825/
https://medium.com/@FAQzine/terry-bissons-fire-on-the-mountain-book-review-b648cbd1392c

So it’s welcome to see a new spin. Check it out, Comrades.  The UASR’s own internal struggle has lasting impact on the globe as well: no ‘manifest destiny’, no Monroe Doctrine.
Online: https://sites.google.com/site/peoplessocialistatlas/
As PDF via Dropbox [link]
Reddit discussion on worldbuilding project: https://www.reddit.com/r/worldbuilding/comments/7xcagp/a_full_200page_althistorical_atlas_i_created/

Alternate History Forum Discussion:
https://www.alternatehistory.com/forum/threads/the-peoples-socialist-atlas.432968/
Thanks, Metafilter!