Well needed post. Despite the incredible emphasis placed on Roman history in the US (and the excessive comparisons), most people know very little about actual Roman history. The next point of subtly you missed, the Visigoths that sacked the Roman Empire were about as “Roman” as anyone else who ruled the Mediterranean institution. Next time your history prof says, “…but it was neither Holy, Roman, or an Empire!” they’re probably stepping into a No True Scotsman Fallacy.
You’re right though. However we define “Romans,” they turned on themselves. Civil War was their bread and butter. Anybody take for granted how important a peaceful transition of power is? Look no further than Rome. Caesar wasn’t even the first to do it. Late-republic was almost as wild as late-empire.
Still, I think the civil conflict was only one part of it. Pandemics, resource management, inflation, and the inability to incorporate displaced populations all played their part. It’s hard to focus on those issues when you’re busy killing each other, and it’s hard to stop killing each other when you have all those issues.
Silver lining: The US (as an organization) has far less in common with the many different institutions that ruled “Rome” than we often think. The world we live in is also incredibly different.
Not so silver lining: We don’t have to look like the Romans. We don’t even need the risk of “falling” like the Romans. It’s always hard to manage shit when you’re constantly fighting one another. Excessive division is no bueno and can lead to no bueno results.
On the other hand: We were more divided during the Civil War; that gave us emancipation. Aren't somethings worth being divided over?