His contrast with the USA is worth noting as a chaser. Rome disintegrated when citizenship became a liability rather than a benefit; "For good and Evil" lays this out crystal clear -- people sold themselves into slavery to avoid it.

That's essentially the lesson for the USA, and we're there right now in relative terms save on one key point. American citizenship by no means has free travel or financial freedom anywhere close to the rest of the west. Massive taxes which bring 0 benefit. The only thing holding it together is the massive resource subsidy thanks to dollar hegemony. The second that ends, the USA ends because they destroyed everything else good about being an American citizen.