I tend to be a Toynbean regarding historical cycles. Civilizations face challenges and their responses determine what course they take in future development. Numerous causes exist for the decline of civilization. Some social constructions experience too much of a challenge to become a civilization. Toynbee at the end of his writing regarded the world as having just one civilization remaining after all the predecessors faded away from one cause or another.
The Roman Empire over expanded commercially. The Romans cared as much for foreign interests as their own. The people-the plebeians, were given bread and circuses in Rome. Too many foreigners were trained in the Roman Legions; Attilla for example, while the rich enjoyed estates in France growing grapes.
The United States isn’t an empire and it isn’t world civilization, yet nations can and do end; the former Soviet Union for example, as politics change or evolve to other paradigms. War is not the only causes for the end of a civilization. Food failures can happen. Plagues can enable rivals to invade, yet the most interesting cause Toynbee pointed out was the inability for civilizations or nations to upgrade and modernize their ossified economic infrastructure. Once a nation is established the economic patterns it follows tends to remain unchanged in its fundamental structure. The same condition prevails to political organization.
Toynbee wrote that Greek city-states couldn’t evolve a national democracy together and thus fell. Toynbee found that Rome evolved a Democracy or Republic in a modern form, yet they could not change their military structure or social structure enough to continue to exist in the west. The Eastern Empire of course continued for another 1000 years after the fall of Rome. The Roman legions just weren’t mobile enough with cavalry such as Attila and Ghengis Khan advanced in blitzkrieg fashion.
The United States as a great nation may be destroyed by moral failures and real-politic failures to reform free enterprise capitalism and democracy to free it from the concentrated wealth problems of corporatism and imperialism. Keeping the national borders and citizenship secure are requisite for any continuing chance for democratic self-determination to be a world leader in reformed ecological economics should that develop. National leadership failure to democratize patents and reduce the period of exclusivity to 3 years with ten percent royalties to the inventor for production thereafter will work against U.S. competitivity. Failure to be a leader in ecological restoration nationally and globally thereafter will reduce the nation to being a part of the problem instead of part of the solution.
The political will for the nation to be a nation rather than a catch-all cul de sac for global capitalists that is simply a phenomenal social nexus of comparatively short life has many challenges to continue including the global broadcast media and pervasive foreign opinion that swamps every place around the world today. To be a strong, moral nation under God, indivisible with liberty and justice for all will require wisdom on the course of the future. That is one very difficult item for politicians to get.