Over the millennia, I’ve seen kingdoms and nations rise and fall. Some nations are created by Divine edict, by military conquest, by discovery, or even the will of the people. However, most tend to die by the same method.
They rot from within.
The wars you’ve seen recently–Afghanistan, Iraq, Vietnam–were all failed or failing states. They either were already corrupt, or ripe for corruption. That’s not only how nations fall, it’s why nations fall.
Through corrupt means, the elites enrich themselves at the expense of the general populace. As the gap widens between the haves and the have-nots, the people become divided. The division may be political, religious, or philosophical, but most often it’s economic. The wider the gap between the wealthy and the rest of the population, the more likely it will devolve into destruction.
Hitler came to power because the German people were economically desperate due to reparations from the First World War. Hitler was an outsider–a non-elite–who was viewed as a possible savior. Lenin was also an outsider viewed as the solution to Russia’s problems. The Nazis and the Communists each set conditions for a division within their country.
Who will be next? There are a number of likely candidates. What’s your guess?