The United States of itself isn’t a civilization. The historian Arnold Toynbee in his final work; Mankind and Mother Earth, provided the opinion that there is just one world civilization remaining on the planet. In his earlier A Study of History, Toynbee studied the civilizations of world history; their rise and fall, to discover similar challenges and responses they encountered in their life cycles. Toynbee believed Western Civilization overcame the remaining others predominantly and merged with them into one world civilization.
Human ideas are shared as was and is technology. The practice of tool kit crossing the globe is as ancient as mankind’s expansion and development. For example, Karl Marx was a Jewish westerner and his ideas became politically influential throughout the globe. Marx was a student of G.W.. Hegel who was in turn the author of the philosophical time The Phenomenology of Mind. Hegelian evolution was modeled in some respects on Christian millennialism stages across history evolving to a pre-determined end. Karl Marx thus got his ideas indirectly from a Hegelian and therefore Christian paradigm ironically. Those philosophical ideas as well as those of Adam Smith were not inventions of the arrested Muslim civilization or the Chinese.
Ideas are shared regardless of their later failure to live up to their initial and optimistic prospects. Corrections to wrong ideas are shared too. Civilization mines ideas the way extraction industries prospect for minerals and oil; globally. Ideas from every culture are sought and brought in to world civilization thought not inevitably with appropriate measure. The United States continues to be greatly influential, as should many nations that keep a sovereign identity though existing within an ad hoc and informal world civilization with an existential political ontology of a common language.
The United States could evolve to a lack of cohesive national identity and that would be a world loss. With the right ecospheric infrastructure leadership by example the prospects for reversing net loss of habitat, mass species extinction and global warming would rise solidly. Nations can be experimental laboratories as were states in the young United States. Instead of forcing a global mono-culture under one overweening dictatorship of world governing authority, nations that are able to control capitalism enough to serve national democracy and political self-determination can show by example with the will of voters to adapt economic and life style modes to the empirical environmental challenges of the day.
World civilization can assuredly end from a variety of causes along with life on Earth including human. Whatever political direction humanity chooses fate could contradict or enhance destructively wrong choices to accelerate the final days of mankind. Reason would indicate that intentional rectification of wrong economic methods that have outgrown the environment is an obligation and duty for political leaders. Yet good human leadership is the challenge. It is so difficult to find leadership with enough experience and education to guide humanity onto a better egalitarian course.