I do have a few ideas for a SaB Expanded Universe, but mostly they delve into technology, particularly space technology, and the Republic of Selene.
Still, with that and your thoughts, might be worth pursuing.
I've been thinking about what the world would look like after the Final War, and it's hard to say just what could happen. Although many of the events portrayed in SaB have real-world historical parallels, there's nothing within living memory that can relate to the apocalyptic conditions of mass death and global societal collapse that happen in TTL's 1980s. It was a chilling set of updates to read, and even though Drakia eventually collapsed under its own contradictions, the whole timeline reads as a downer in light of the ending (to say nothing of the "normal" atrocities and disasters). Nevertheless, it's interesting to really dig into the long-term impact of these events.
My thinking for SaB's United States is as follows:
after Drakia falls apart in 1985, the government of Acting President Victoria Valverde is relieved. They were prepared to defend their territory from Drakian expansion, but instead they work with General Reeves' administration in Josephtown to push the "American Empire" into surrendering. On paper, the United States of America is restored. Hooray! In reality, though, there are still multiple state governments that aren't picking up the phone. Some are mollified by assurances that whoever managed to survive the chaos of *checks notes*
orbital bombardment, multiple pandemics, and foreign invasion will be allowed to stay in their posts, even if the line of succession is anything but clear. The federal government has no real choice but to accept this, since other parts of the country are even more lawless. After all, the same dynamics of warlordism in places like Europe still occurred, even though they prefer to claim the mantle of the United States as "emergency governments" and are mostly composed of National Guard units, ad-hoc groups of local communities, and things like that. (I read another timeline by EBR called
Stars and Stripes Forever: America After the Apocalypse which explores how an extended all-out nuclear exchange would collapse the government and what would eventually happen, and even though SaB's Final War is less brutal in some ways and moreso in others, I think it has plausible similarities that could be adapted.)
The rest of the decade is spent mopping up the various rogue states, warlords, and bandits, using the carrot (vaccines) more than the stick, until central governance is restored to some degree. Only a few states remain independent, two (Quebec and Haiti) with the tacit consent of the US government. However, this is the time when climate change starts really hitting hard. Places on the coast that may have had some hope of rebuilding previously are now doomed to languish low on the government's tottering list of priorities. For example, the West is experiencing a severe water crisis that sets off another wave of refugees, and the government manages to relocate many of them north even though the whole thing is a massive headache. The local authorities in various states need to be "guided" to hold free and fair elections—although it would be nice if they all chose to leave office after serving a duty they most likely didn't want or expect in the first place, there are other cases where the individuals in charge have grown accustomed to the power they wield and don't want to give it up, whether for personal gain or because they genuinely believe things would collapse without a stabilizing influence. Overall, there is a rally-round-the-flag effect that continues after the most immediate crises are resolved, but national trauma is never pretty.
In terms of party politics, I'm not a polisci expert, and post-apocalyptic scenarios aren't my usual cup of tea so I'm not sure what's the norm. However, I did have some thoughts on this as well. Genuine democratic involvement would take years if not decades to materialize. This would be due to a number of reasons. For one, the basic issue of being able to know who's alive and able to vote would be a bit tricky due to the mass death, damaged infrastructure, and loss in administrative capacity. The 1990 census would probably be rife with missing or misreported data, although they'd probably have more success collecting data ten years later. However, even if they did pull it off perfectly, it wouldn't matter much to the political process at this stage. The various surviving politicians came from a variety of parties, but under the circumstances they would govern as nonpartisan officials for the sake of national unity. In any case, those parties would be utterly disorganized and nonfunctional, making political contests harder even if they wanted to compete on anything. Still, democratic principles were largely adhered to, and elections were delayed as little as possible. People still turned out to vote, even though it may have just been going through the motions of normalcy. Thus, a variety of independent candidates started cropping up in the mid-90s, running on local issues or simply force of personality. Some of them won, but the nascent establishment pulled through mostly unscathed.
One way politics could really start up again in earnest could be the retirement of President Valverde. I picture her as serving two elected terms in addition to her self-appointed stint as Acting President, which would place the end of her tenure at the election of 1996. By this point, the supporters of her administration and the political status quo in general would have coalesced into some kind of party grouping. I was thinking of calling it the "Alliance Party," short for "Alliance to Rebuild America" or something equally institutional-sounding. Their nominee would sweep the election against whatever challengers emerge, but many people would be able to think beyond their present conditions now that they're not immersed in chaos and danger, and this would naturally give them the opportunity to finger-point at why things are still kind of broken. Leaders interested in maintaining power would find that it's increasingly difficult without trying to appeal to a specific voting bloc. Thus, partisanship!
There are any number of ways this could go, but my idea is the creation of a new party from the ground up. The threat of pandemics or the distance of disconnected areas with subpar infrastructure would not disrupt organizing like they had in the past. Instead, these activists would use the internet to organize local Committees of Correspondence, inspired by the ones that existed before the Revolutionary War (like the Green Party founders were IOTL). These committees would metastasize into a decentralized organization advocating for
democratic confederalism and
ecosocialism, which would be eventually known as, hmm, let's call them the Humanist Party. Now, would this group be called a "green party"? I'd say yes, but it's more complicated than that. Climate change and the necessity of changing human activity to solve it would be a universally accepted truth in the government, so you'd think their mission is complete. However, the Humanists' thought leaders alleged that the problems of capitalism, militarism, and general lack of regard for human life need to be solved by revolutionary change. Peaceful, yes, but revolutionary. They criticize the Alliance Party for focusing on an imagined "return to normalcy" rather than recognizing that reversing the immense damage inflicted on the world is impossible. They argue for policies like establishing co-ops to replace the subsidies the government had been pumping into the tattered remains of corporate America, and generally want to avoid returning to the wasteful system that led to the climate collapsing.