A shorter summary (I was reading The Republic in 2018) ...
Everyone should stick to what they are good at. Sculptors and potter decorators are not politicians. Politicians are good at politics, nobody else is. And politicians shouldn't interfere with other skill sets. So democracy is a big no-no. If you are lucky enough to have competent politicians, then the Public needs to shut up and get back to sculpting and pottery decorating. That is the first rule. The second rule is how do we obtain competent politicians? The Guardians. A lot like Thomas Jefferson proposed for why scholarships should be made available to the University of Virginia ... talent will rise, but you don't know from where. You identify it early, and direct it into where the talent can best serve. If your natural talent is politics, then you need to be assisted and directed to take a course of training that will maximize that talent.
The people Socrates is speaking against, Thrasymachus et al ... believe in democracy (rule by incompetents) or in tyranny (rule by violence). From Socrates' perspective, democracy was a cheap trick by Cleisthenes (508 BCE) to extend the effective franchise so that his opponents, a narrow land owning and mercantile oligarchy, could be overcome (because they created internecine conflict internal to Athens). Having done this, the People needed to be persuaded to do the right thing by oratory (Peitho is the goddess of persuasion) ... at least in the common mind, this is a religious act. Pericles was the early master of this (later Isocrates and Demosthenes). The events of Socrates' life told him that tyranny was wrong (Peisistratus was the most notable Athenian tyrant) and that democracy was wrong (Cleon was the most notable demagogue). A tyrant, in Greek, is not as negative as it is in English. It simply means rule by one man, not a committee of oligarchs or an assembly of free men. Peisistratus was responsible for the epic poetry contest in Athens, the resulted in the "received text" of the Illiad and Odyssey. Unfortunately, this two sons, Hippias and Hipparchus wanted to succeed him, and didn't have his talent and chaos resulted. Hipparchus was assassinated over a gay love triangle. Hippias turned paranoid and repressive. The Athenian oligarchs called in King Cleomenes I of Sparta, to force the end of his regime, and Hippias went into exile.
It was shortly after that, that Cleisthenes used the mob to end the resumed chaos of the oligarchs that Peisistratus had ended. Hippias went on to the Persian court of King Darius I, and was instrumental in getting the Persian fleet/army to land at Marathon, in a bid to restore him to power, to end the hostile Athenian/Spartan policy of undermining the Persian Empire in Asia Minor, including the looting and burning of Sardes. Sardes was a source of wealth, the capital of the Lydian Kingdom, which was conquered by King Cyrus in this same period. Lydia and neighboring Greek sea coast colonies (Ionia and Aeolia) were the originators of coinage.
Basically the whole democratic period from 508-399 BCE was a disaster for Athens and for humanity (as seen millennia later by us). Except for a brief period of leadership by Themistocles and later by Pericles, the average politician got the assembly (at the Pnyx) to do one folly after another. The worst being Alcibiades (who was prominent after Cleon, who died in combat at Amphipolis of his own stupidity) ... who led the Athenians to the disastrous idea of invading Sicily and taking Syracuse. Folly continued right down to the day that Athens, which had to import its food, was starved out by Spartan blockade (who by this time had their own navy, courtesy of the Persians). Alcibiades was one of Socrates' younger lovers and the treason of Alcibiades is what got Socrates executed "guild by association".
There were a few decades of Athens as a lesser version, in the decades after Socrates was executed, under Isocrates and Demosthenes. But by this time King Phillip of Macedon and his son Alexander, brought back monarchy in a big way, and not even Sparta ever recovered from that. Athens was a dependency from then on until the modern era.
I am a long time fan of the classics (Greece and Rome). I will never drink the last drop from that bottomless well.
