1889
Mayor of H-Marker Lake
I'm just trying to anticipate a potential problem. Another civ has a slight lead in the space race, but is really weak and if attacked may ask to become my vassal. If so should I accept?
That is very helpful advice Joshua. Could you tell me how to control vassel research? Is it done on the diplo screen?
Vassals can win Diplo, Space, Time and Cultural. The other conditions are out for obvious reasons.
So if you want to be ultra-technical only conquest is impossible, but none but space or culture are likely (vassals aren't usually big enough to be eligible for diplo wins via UN, and if they're AP you can kick them out of their religion).
score/domination
Vassals give half their score to the master? Do they keep their full score and it gets added or what?
So... now we need to play a game with your fancy AI and make him get a domination victory. Capture cities, liberate back and hope he stays with you.
Then we need to do it with only liberating some cities, and it would have to be a voluntary vassal.