Athens demanded tribute from its allied city-states – we give our money away. Those allies weren’t so much asked to join as they were forced in many instances. Our "allies" tell us that we are bad and condemn our actions, and we don’t exert any sort of force or even economic pressure.

Athens lost that war because it over extended itself in its Sicilian Expedition.

Athens was no less brutal than the Spartans on many occasions.

The deck of cards was the list of bad guys to be captured – not executed en masse. I believe the list being addressed in the novel is more along the lines of "we have defeated your Army, now we will round up the following people within the city and execute them." The bad guys on the deck of cards were all soldiers, criminals or turned into insurgents, not innocent politicians.

Additionally, the Peloponnesian War was more similar to the Cold War than it is to this one, strategically speaking, with 2 major powers going against each other, and everyone else being forced to choose sides. There were some outside influences, but it all came down to Athens vs Sparta.

Ok those are my initial thoughts. I’d like to add more, but I need to take some time and formulate my thoughts better.