The mechanisms of a collapse are not quite the same as its cause:
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"The historical truth, if any exists, is that Rome did not fall; rather, it evolved. Roman coloni (farmers tied to the land) gradually became Medieval serfs. The patron-and-client relationship, so central in Roman society, slowly assumed the name and nature of the lord-and-vassal bond, the social order underlying much of European society in the Middle Ages. So, if Rome fell, it was only in slow motion, very slow motion.
But change did come to Rome in the fifth century—as it has to every society in every century of human history—and a particularly drastic change it was. Many of the conventions which had once ruled the ancient Romans' lives evaporated, never to re-emerge. Primarily, citizenship in Rome offered little or no protection to its denizens, like membership in a club that was now defunct. That, in turn, precipitated an even more serious casualty, the loss of pride in being Roman, and of all things that perhaps lies at the heart of the problem. When being Roman no longer mattered, then being Greek or Dacian or German didn't either, and if their Romanness stopped giving people a sense of military or economic or racial superiority, what was the point of being Roman?
This bigotry, evidenced well before the fifth century, cuts to the heart of the myth about Rome's fall. In simple terms, the nationalistic propaganda of late Rome included a good element of racism which held that Germans, while useful in some respects, were fundamentally aliens, something less than Roman, to many in the day less than human. So when barbaric groups of Germans first defeated the Romans in battle, then captured Rome itself and finally assumed the mantle of Roman authority, it looked to those who saw "Roman" and "German" as mutually exclusive terms as if the Empire was no longer Roman, no longer an empire at all. But this was, in fact, a rationalization, an excuse concocted by the late Romans to cover their own complacency and lack of planning, which was, to be frank, rooted in laziness. Thus, lethargy and bias lurk behind the notion that 476 was a date of any supreme significance, much less the Armageddon of the classical world, the moment when "Rome fell." "
In short - Rome ceased being Rome.
The embracing of cultures other than the Roman culture as being a part of Rome is what ultimately destroyed Rome.
Borders. Language. Culture. Without those three things, you do not have a nation. This is why France was able to survive its bloody revolution. France was still French. Frenchmen still spoke French, and the culture was still French - even if there was an ideological cleansing.
Who is "the people?"
That, right there, is why you will be perpetually surprised and confused by the things that happen in the world.
There is no "people" to act against. There are persons.
There are many, many persons who are currently terrified. The police they pay for are given orders by political limp-dicks to stand-down and let stores and homes burn while people are bludgeoned in the street. The laws of the society we have made ourselves a member of mean nothing before the power of race riots.
That scares the shit out of people.
Unless the State does something to uphold its laws and make being a member of it worth the taxes - you can bet that what I just described will be the civilian response to riots in the coming years. People will take to the streets with their weapons and will kill the rioters - prompting a defensive response.
And our nation will descend into civil war as it has been planned.
Why would anyone ever want to live in a place like Boston - where they mayor says: "They need space to destroy" - your home. Your business. Your place of employment. Your favorite location to hang out.
Why pay taxes to a system that will not make due on its most basic of responsibilities to secure your property against large scale threats?
The reason why totalitarian states fail is because the succession of power eventually fails. Someone gets clever and usurps the authority. It has very little to do with brutality. North Korea is stupendously brutal to its citizens and has been one of the most successful totalitarian states in preserving its line of succession. It hasn't broken the unity of the people. In fact, it's only made them more unified. Everyone loves Kim. Those who don't are shown how affectionate hard labor is and learn to love being allowed to not do hard labor.
Likewise - Germany was exceptoinally unified under Hitler. Hitler capitalized on the German sense of their 'tribe' being smarter, stronger, and more capable than others (Racial Superiority and Nationalism are very similar concepts in Europe as one implies the other) to unify Germans against those who were of foreign ancestry in their midst (most notably, the Jews).
And the Germans conquered the bejeesus out of Europe, Asia, and Africa. If Hitler had been smarter in his strategy, much of the European world would be speaking German and paying taxes to Germany as if it were the seat of a second Roman Empire. Logically - there is a limit to how much Germany could practically conquer and keep under control - but vast portions of Europe had already accepted German occupation long before it became a "World War." Some countries would argue that having the Germans in charge of their districts was an improvement over what they had going on their own.
Germany didn't fail because they embraced "brutality" - but because they were impetuous in their drive for conquest. They over-extended and made far too many fronts for themselves. When America joined in the war - the only hope the Germans had at that point was fighting the U.S. to an economic stalemate - making it so costly to fight a war for Europe that we packed it up and went back home.
Basically - Hitler was stupid when it came to military strategy and assumed he could somehow rally the Germans to take on the whole world.
Stalin and Mao were both entirely successful in their cause.
Did they establish functional systems? No.
The point is that it was a group of persons who elevated the dictator to his/her status in the first place.
Likewise - Russia collapsed when there was no longer reason to be a part of Russia. When the acts of the government begin to make it so that people have to become criminals to survive or to go about their lives in any meaningful manner - then that government will eventually collapse. Distant populations will seek independence and local populations will seek revolution - a change of authority.
You will rarely find instances where a nation has a revolution and actually prevents its government from using death and destruction. In the case of Germany - the government was literally overthrown for the purposes of seeking conquest and of breaking out of the various treaties imposed after World War I.
Death and destruction are parts of the human instinct and, in some cases, part of the preservation of a society's laws. If someone is holding you down and raping your ass - you aren't going to be too concerned about the methods used to stop the violation against you. Maybe a favorite heirloom gets destroyed when Tifa Beat-rushes your assailant and half the stuff in your room as a consequence. It's unfortunate - but at least the rape is over and Tifa turned the perpetrator into a crater.
Society is much the same way. Perhaps blowing up a town is a little excessive, but at least you know that people who try to burn down your house or your store will not be tolerated and that your dislike of such behavior will be supported.
Right now, what happens?
You don't like the riots in Boston? Call them thugs? Well - you're a racist. Or you're an Uncle Tom (or... Aunt... Tristie?) "You" are part of the problem and need to 'understand' these people who are tearing things up.
But - you're still foolish enough to believe there is actually a United States of America.
That illusion will be coming to an end before much longer. Though I am sure it will surprise you when it does.