The only time a republic and a democracy should preclude each other, however, is in a game of Civ 2 
ARRRGGGHHHH!!! Don't mention that awesome game or I might start wasting my time playing it again!
Even though that I have figured out that all upping the difficulty level does is give the AI opponents resource boosts and impossible abilities to regrow city levels, and replace lost troops instantly...
I mean...seriously?! I hit a level 10 city with a nuke, which should set it back to level 5, but on the next turn it's level 7, and then gains a level every turn until it's back to level 10 three turns later???!!!
AND can also manage to restock Alpine Troops every single turn??? Their economy is unbreakable!!!
Fair enough I suppose, considering that the AI is pretty stupid and wouldn't be much of a challenge otherwise: They mass their ship fleets and hover around one of my cities that is a square inland and that they can never attack...
If this otherwise perfect game could be rereleased by a fan/hacker which fixed all the AI bugs, made the opponents smarter instead of just giving them impossible buffs per difficultly level, and fixed the travesty of air units not being able to overfly enemy units without attacking them...
It could be the greatest simulation game ever made...
/Grinding my gears on a decades-old game...