Raise yo taxes. lol I swear, once your production is at a certain level, you can tax at 100% without any significant dent to production.
At 100% tax one would think a "normal" civilization would collapse, because why would anyone work anything if they would receive no money for that?
Either all work is done by machines (what would mean "100% tax" then?) or it some kind of communism or whatever
Who says it's income tax?
Ok, may be value added tax or something
Whatever, in my first (not very advanced yet) Intrigue game I taxed my people with 80% out of necessity and my approval fell down to 0% on all my four planets, resulting in very severe penalties. That's a change to pre-Intrigue that I really appreciate. Now approval is really important (at least so far).