Financially, militarily, socially, and internally. Best that Americans just abandon hope and look towards the future.
In your estimation, what is at the rootO of the decay? How should the future deviate from the present?
I offer up capitalism as the root of the decay.
I believe the American country, American nation, and American state are three different concepts. All three are in decline.
The American country, as in the actual land of America, is in decline primarily due to disregard for the environment. The American nation, as in the people and culture of America, are in decline due to a loss of public consciousness and divisiveness due to politics.
Now the American state, as in the actual government and military that composes the United States, is in decline due to fiscal irresponsibility, widespread corruption, outdated thinking, loss of public consciousness, internal and societal rifts, failure to maintain competitive trade relationships, ect. The greatest reason in my opinion is a loss of public consciousness, since it is absolutely vital that a ruling state presides over a strong nation, and the American nation is losing its identity and culture.
I have plenty of radical opinions on economics, and am a vocal critic of state capitalism. However I would not characterize state capitalism as the underlying reason for the decline of the United States, since literally every state on earth engages in that economic philosophy.