Wouldn't be too hard to keep them in line when you can just start carving a planet like a cake with the Hades if they get out of line. Sabotage a ship? A city gets wiped off the map.
Once again I have to point you towards the Nazi's practices of forced labour and why they didn't work. In essence, you are already illustrating the issues with your own point here: You now have to employ military force in order to keep the slave population in line. That's a pretty big military investment, made bigger by the fact that you're now killing your own workforce. A workforce that, in the GTVA, contributed to all aspects of the military. This harkens back to my original point: When you're at the point that you're bombing cities to keep the population in line, you don't have an effecient military force - or at least, one more effecient then the GTVA.
You'd be able to tell the difference between such normalcy and sabotage though, surely?
See above. The Nazis often weren't able to tell, needed a lot of people to make sure that they could tell, and had less and less people to do that as the war progressed (since those people were needed at the front).
Let me ask you a very simple question.
Who do you think is going to work harder?
- A person making military equipment for an army that their family members or children or spouse are in
- A person making military equipment for an army that killed their family members, children or spouse
The former was practiced by the Allies, the later by the Fascists. You can take exactly one guess on which side had more effecient military production. And yes, I'm aware that I've been criticized for using an example from the past to extrapolate 300 years in the future, but I darely say that my examples are more recent then...
Besides, you don't have to have the Vasudans doing such things, though you'd want to take advantage of their skilled personnel if possible. Instead, it could be like every great empire in ancient times, with slaves doing menial work to free up the Empire to be doing other things.
... this thing right here.
So, first of all, we don't live in ancient times anymore. Menial tasks have been replaced with machines, and we can except this trend to continue in the coming centuries. You can see this trend in forced labour today as well:
The United States employs roughly 800,000 forced labourers, not 150 million. Most modern legal frameworks that exploit labour are far less overt then this.
The Kafala system in the Gulf states springs to mind as the most well known example, with the usage of an Exit Visa system (ie "You can't leave unless we allow it"), which has been marked by human rights watch as effectively forced labour. But there's a big difference between these systems and what you're proposing: The US's forced labour population comitted crimes and is less then 1% of the population. The gulf states's forced labour involves people from all over the world who ultimately choose to be there, and the gulf states have been forced to change the system under threat of revolt.
There's arguably less of a reason to even talk about ancient states, as ancient states used slave labour for things that are now done by machines. But let's do it anyway!
First of all, we should probably acknowledge that even the Roman Empire, that really started putting the whole "enslaving entire populations" into practice in the first century, never had a relative slave population in Italy that exceeded 30%. And here too, the slave population came from all over the empire, and even Rome's subjegated peoples (and even slaves) had some form of social mobility. Even then, slave revolts were a concern.
None of this is present when you propose enslaving the entirety of the vasudan race. There's three problems here:
- Roughly half of your population is now enslaved (unless you start massacring them, but then you'd already have a smaller workforce then the GTVA baseline)
- Everyone you have enslaved has a common langauge and heritage, making it easier for them to unite
- Since the slavery is tied to being a vasudan, the vasudans have nothing to lose but their chains
All of these make the system ripe for a revolt. The only system in ancient times that is close to this is the Spartan system of
Helotry, but the spartan system of helotry came at a huge cost: The entire social structure had to be reformed in order to supress slave rebellions. The purpose of the army was to kill slaves. Armies were trained by killing slaves. Gaining power in Sparta under the helotry system just meant that you had more slaves to kill, and your responsibilities revolved around killing slaves. Which brings me back to the point I made all the way at the top of the first post: If you're busy supressing slaves, you're not building an effective countermeasure to the Shivans, something that the entire GTVA revolved around.
And yes, the Spartans are praised as a effective military force, but this is very much a case of the popular imagination not aligning with historical reality.The only way to make this system sustainable (if it even can be implemented because although the rogue GTI faction may have won in our scenario, they don't exactly control the conscience of all mankind) is for the vasudan population to be massively reduced (again, less effecient), or for the Terran population to be reunited with earth.
Which, as you may know from having played FS2, needs the Knossos portal to be found and stay open, thus inviting the Shivans.
There is simply no scenario in which the GTI could subjegate the Vasudan population and be more effecient at shivan killing then the GTVA.