If history's proven anything it's that if you put enough humans together we'll do almost nothing but invent more and more elaborate ways to kill each other. And sometimes to kill other things too.
And in the end why not just replace the citizenry and voters...
We could lock up those imperfect humans and just occasionally ship them some food and water. Maybe direct them to not produce so many imperfect new humans too.
If AI can be a perfect tutor, it can certainly be a perfect parent, perfect romantic partner, perfect employee, perfect employer, perfect VC...
In fact why not create a perfect economy, perfect media, and a perfect infinitely wise and knowledgable political system?