the Imperial Commonwealth absorbed, largely without fighting
Still trying to make sense of how assimilation by Imperial Australia works. If I've got this right, the Empire is essentially a combination of the feudalism of the medieval HRE and colonialism of imperial britain, they show up and offer free trade with the local goverment in exchange for concessions (essentially, 'our laws supersede your own, pay us
protection money taxes, get levied to fight alongside us if necessary and don't build weaponry technologies that are threatening on a specieswide scale, in exchange, we'll share some of the bounty of our technological civilization and defend you from anyone else who tries to conquer
our imperial possession'), with being told to go away being met by offering the same deal to local rivals of the official local goverment, so that they can use their foreign backing to overthrow and replace the official local goverment. Since at the time of their world conquest, Imperial Australia possessed enough of a technological advantage (probably around eighteenth to nineteenth century britain equivalent) to make themselves a very attractive trade partner and effectively indefatigable in comparison to the scattered technobarbarian tribes of the rest of the world, they were able to eventually succeed at unifying the entire planet.
The Empire was ideologically motivated to do so, by the commonly held assumption that the existence of multiple rival civilizations possessing technological capabilities sufficient to end the world was an unacceptable risk, which could only be resolved by one civilization successfully conquering everything immediately, in the present era where everyone only possessed 'safe' levels of technologies, before doomsday weapons could be reinvented.
The duals showed up a couple decades, maybe a century at most, later, once the technologies to create them were invented, the implications opened by their existence causing massive chaos and ideological arguments among the highest levels of Imperial goverment.
- The Empire knew it couldn't simply outright ban the technologies, since 'perfect health and triple baseline lifespan' was enough of a lure to keep people augmenting their progeny despite the illegality of doing so, which would inevitably lead to the existence of a persecuted and hated minority of genetically enhanced superhumans, which itself would inevitably lead to World War Five* in which said genetically enhanced superhumans developed a Master Race complex ideology around being oppressed by baselines and evened the score.
- They knew they couldn't simply let the free market handle it, augmenting anyone able to afford it, like themselves, since they were smart enough to recognize that this would inevitably lead to a world where the baselines were permanently locked out of all but the lowest positions in society by qualifications raised unobtainablly artificially high by competition with the standards set by genetically augmented supermen, which would also lead to another version of World War Five*, global anti-apartheid revolution with genetically augmented supermen as the afrikaaners.
- They knew they couldn't just make it mandatory without ticking off every single group from the perfectly reasonable paranoids who'd immediately suspect that any form of mandatory transhumanism was an excuse to forcibly addict the entire peasantry to ketracel-white and rule forever by monopolizing the supply to the mark-of-the-beast nutters.
In the end, making it voluntary but subsidizing it for everyone who wanted it was the best option.
* #3 was the Cataclysm War between the American Empire and China, #4, the Australian Empire Planetary Unification.