It's the main criterion. If the system doesn't last, then it's shit regardless of what it is. The main purpose of the government (and any organization, for that matter) is to exist for as long as possible, everything else comes second. I wonder what other criteria do you have in mind?
The argument is that they were a democratic republic.
several popular assemblies of all free citizens, possessing the power to elect magistrates from the populace and pass laws; and a series of magistracies with varying types of civil and political authority.
If you're referring to direct democracy, I suppose we could consider the Athenian democracy, though I think there are other examples from different regions on the planet through antiquity.
Popular assemblies composed of common citizens could maybe decide where to put a public toilet on a street. Most laws were passed by the senate (composed of aristocrats), and consuls/other top magistrates were appointed by the senate.
So you were there and knew everything about it? Are you going to provide some evidence of whatever point you're trying to make, or should we do this tit-for-tat some more?
Either way, no sweat. Happy to yell at the clouds with you until the heat-death of the universe.
Will you provide any evidence for your claims? It's not me who's claiming Roman republic was a democratic state (lol). "popular assemblies composed of common citizens" lol, look up centuriate assembly and see how many votes common sitizens had in it (spoiler: 0.5% of total votes).
It kinda is, everything falls on that scale, either people are being represented and representing themselves or they aren't. Everything else is just the mechanics of that.
Roman Republic exited for 500 years before Roman empire. They were the first to implement the division of government into 3 branches, so I guess they weren't a dictatorship? They actually invented the word "dictator". It was temporary authority given to the head of the state at the times of emergency. So, most of the time Rome wasn't a dictatorship. And it wasn't a democracy.