Right now, population is a complete hindrance. See here : https://drive.google.com/file/d/1gM8oTx570AZ7DZAImFMh_17IPDNjSvSq/view?usp=sharing
A higher population should affect the GDP and your income (if you manage to keep a high GDP per person, which can be tricky with global warming and resources depletion). Having a global population in the same way you have a global GDP could be a way of implementing this. In order to keep the population in check, a territorial / inhabitable land limitation could also be considered, but that seems to add a lot of stuff to the game… (maybe warfare ? now it’s sci-fi territory !).
This problem was already present in Democracy 1 to 3, if I believe the “Your topic is similar to…” It would be nice to have such a mechanic in the fourth iteration of the game. 