"A republic, if you can keep it."
Note the “You” in this sentence.
This is a key word; once a system of government is set, its continued survival depends on the will of the people to maintain it.
The Romans once had a republic, but then decided to trade their votes for the “panem e circences” provided by powerful Tribunus. They had actually made a pretty good deal; rather than ceding some power to the Plebeians,
Res Publica Libaniensis
Today, the world has no democracies; only representative republics. Rather than giving people a direct say in the affairs of the state, representatives are elected that do that.
The upside is a more balanced system, shielded from the perceived excesses of the Athenian democracy.
The downside is that, once in power, those guys will do their darnest to remain there, even at the risk of toppling the entire system. At the end of the Roman republic, the absence of a voting mechanism meant that a civil war would come to sort out the two potential dictators vying for Ceasar’s “chair”, Octavius and Marcus Antonius.
Some arrangements work, others less so…