For the moment I wanted to put out snapshots of two very different sets of political and governing ethos.
The Byzantine Empire had a very strong centralized state. Part of the reason for this at the time was that it existed in a severe, austere post-collapse environment in which it had sharply limited resources and was surrounded by powerful rivals, and much of the empire's remaining power came from its persisting ability to organize and supply itself within the protective shell of Constantinople itself within a more sharply delimited geographical space.
After the expansion of the Arab Caliphates cooled, and their relations with the Persians and the rest of Western Rome normalized, the Byzantines were able to spread out a bit again and regain some breathing room, but it did have to pander to oligarchs to do so, who were regional military powers doing the work of cultivating and fortifying their own regions with their own military forces and holding those regions outside of Constantinople. But the empire was able to keep a pretty tight leash on them, and was very wary of them as political rivals, who depended on the empire to survive in the conditions they found themselves in.
On the other hand, it is very rare that you see the United States even reigning in its oligarchs; on the contrary, it is often led along by them and governs through them and them through it. Historically the US has enjoyed an abundance of defendable land and resources to expand to, and exists in the modern era itself which is typified by an explosion in material wealth, technological advancement, and energy utilization.
The US itself has derived great power from letting the oligarchs run amok: engaging in adventurism first in the frontiers of its own virgin land and then eventually throughout its colonial holdings, and then benefiting from the vast material bounties afforded by them letting loose, and they benefitting in turn from US encouragement and protection.
We've come quite a ways from the initial period when its founders were wary of such things, sentiments which went away pretty quickly anyway, and in our contemporary political culture the power of the oligarchs is a thing to be trusted and celebrated - though this is quickly going away - and that their temporary leashing in the course of the New Deal was somewhat regrettable and mistaken, though of course the liberals will express just the opposite in their pronouncements while engaging wholeheartedly in free trade policy in practice.
