BFLR
VDH does a good job based on a single main source. But also there are things like how selling Roman Citizenship which became essential for the imperial cash-flow and the resulting devaluation of said citizenship impacted the Empire is very similar to today as well.
My take has been that the most valid analogy to Rome with America is that both states found out that a Republic is an excellent form of government for a relatively culturally homogenous people forming a nation, and an impossible form of government to maintain when running an empire ruling (or heavily controlling) many other nations.
A massive influx of those who don’t want to assimilate and are only there for the economic benefits doesn’t help a damn bit, of course.
But a Republic didn’t work for Rome very well once it expanded too far, into the spaces left after the defeat of Carthage- and after WW2 we’ve faced the same problem; we essentially had/have an empire stretching across a big chunk of the globe, and the lean, non intrusive and moral type of government designed by the founders didnm’t work for that.
The Western Empire and Rome itself fell around 400 AD, overrun by waves of Goths and other barbarians. The Eastern Empire survived another thousand years until Islam conquered it.
Europe is repeating that destruction with waves of “migrants”, in an act of civilizational suicide. We have been doing the same with mass immigration, legal as well as illegal, with California being the example of what is coming for the rest of the country.
The most obvious similarity is the pacification of The Mob by Bread and Circuses, or Welfare and Internet/Cable in our case.
As long as cable is up and the EBTs refill every month, I think folks will be too apathetic to start anything major.
Once one or the other fails, it’s on. Bored or hungry people are dangerous.