One Thousand Sunrises
Here’s how it is …
The Earth got used up. So we found another solar system, and terraformed dozens of new Earths. The Central Planets formed the Anglo-Sino Alliance and called for all worlds to unite under their rule. There was some disagreement on that point.
After a long and bloody Unification War, the Alliance got what they wanted. Or so they claimed. Least now everyone can be interfered with or ignored equally. Many of those who fought for independence drifted to the outer planets, far from Alliance control, where folk try to scrape by with the most basic technologies and right and wrong can get a mite fuzzy.
Most tried to forget the past and move on. But for some, the war will never be over.