The more interesting period politically is the ascent of the Gracchi, who consistently violated unwritten political norms. The response of the establishment was to murder them, as there was no institutional mechanism to reign them in.
The Gracchi brothers, Tiberius and Gaius, were Romans who both served as tribunes in the late 2nd century BC. They attempted to pass land reform legislation that would redistribute the major aristocratic landholdings among the urban poor and veterans, in addition to other reform measures. After achieving some early success, both were assassinated by enemies of these reforms.
The saga of the Gracchi is when the cracks in the Republican order first began to appear. This pattern of norm-breaking back and forth between progressives and reactionaries would repeat until there were no norms left and it took six decades of civil war until peace and stability was restored by the imperial dictatorship.
The story of the fall of the Roman Republic is not so much a story of the decay of democratic or governing institutions as we know them as it is the story of a ruling oligarchy that gradually loses the ability to discipline its own members and keep them united in a common policy.
"democratic norms" are behaviors in the public sphere that are expected under the assumption that politicians are interested in the good of everyone and that the popular will has political meaning.
"progressives" are politicians who want to improve society through reform and the redistribution of wealth and power.
"reactionaries" are politicians who want to return things back to the way they were before progressives existed.
These terms are perfectly appropriate to describe the political climate in the late republic.
You keep asserting that there was a "ruling oligarchy" when this is simply not true. If Rome was ruled by an oligarchy, then the Gracchi never would have got off the ground.
It is a historical constant that rich people are more likely to find themselves in office. Campaigning takes time and effort and you don't get paid for it, so you pretty much have to have some wealth stashed up before you can run for office. That was true then as it is true now.
That doesn't mean that there has never been a democratic government in all of history. No matter how wealthy you are, in order to get those jobs, you have to convince people to vote for you.
I'd really urge you to crack open an academic textbook on the subject. If you'd like to dive a little deeper, I'd recommend W.G. Runciman, "Capitalism Without Classes: The Case of Ancient Rome" (British Journal of Sociology), Wilfried Nippel, "Policing Rome" (Journal of Roman Studies), Peter Baehr, "Caesar and the Fading of the Roman World", Peter Brunt, "The Army and the Land in the Roman Revolution" and Douglass North, "Institutions, Institutional Change, and Economic Performance" which has a large stretch of summary of Roman political economy.
The sky isn’t so much blue as it is light that has a wavelength around 450-495 nm.
I understand that a historian would take great offense to the anachronism you’ve pointed out, but I still can’t help but to think that we’re describing the same thing with different words. Yes yes, words matter, but, there’s some underlying truth about when groups of apes stop being able to govern themselves that comes out, no matter the words.
When people are feeling desperate, and it's become clear that the system is not working, it's easy for populists to come in and promise to fix all the problems if only you'll let them do away with that pesky free press, and take votes away from those frustrating opposition people, and get rid of the annoying rules about making profit while in office.