Seems like the “break” happened with Julius Caesar vs. the dying out elite (that cultural/political split which was driven by the criminals who financed the Julians through the Aventine and wheat). So long ago and they did not have a Constitution such as we, designed to escape the European Monarchism (which Rome preceded by many centuries of course).
Then Pompey vs. Mark Antony... what a story. The end— far reaching Roman Empire “citizens” swooped down to destroy the entire place and the fabric that held that system together.
The American Republic (or is it now Empire?) will meet a similar fate.