The post WW2 and Cold War period is our defining moment. When the history of the Earth is written, if we only get one paragraph, it will be about that moment. Hard to think of it as the beginning of the end.
Perhaps we have always been destined for failure. We have always redlined everything. Manifest Destiny, Military Industrial Complex, whatever the fuck this is now. Take your pick. Eventually, the engine gives out.
The main problem with America, and really the reason all the knee jerk Trumpist patriots exist, is that the term "American" is largely undefined. Germany, Russia, France, England, China, Japan, etc, have all had multiple types of government, revolutions, and wars. Yet all of those "identities" still exist. Latin American countries have had multiple types of government, but still exist. Cubans remain Cuban under Castro-ism. Even English speaking Canada would still be Canada under any type of government. But America is over with if our government is over with. Sadly, that is also the fault of the knee-jerk patriots who pretended they wanted us to be a group of loosely affiliated independent states that only get together to fund a military and print money.