The model for what happens to Democracies was ancient Athens. Plato lays it out pretty well in The Republic. As did a number of other classical writers, Greek and Roman.
Yep - started the Dole and the inevitable happened...
Rome had a pretty impressive Republic, then the likes of Marius and Sulla came along - ever pushing the boundaries of unlimited power for longer and longer periods. By the time Julius Caesar arrived on the scene, there were very few traditional “Republicans” left as the “bread and circuses” crowd far outweighed the traditionalists. Even so, the transition from Julius to Imperial Rome took 17 years, and stayed that way for centuries.