When you look at the historical rise and decline of societies over time you see a lot of the same factors - overstretched militarily, problems sustaining the food supply, problems maintaining critical infrastructure and a declining stock of leadership.
In the US we face military challenges in a host of different countries. Food prices are on the rise because of our reliance on oil in the production cycle and because our strategy to resolve the oil dependance is to use food (corn) in our gasoline to strtch it further. Our roads and bridges are a disaster, our air traffic control system is in major need of improvements, and the news on our ports (at least what is written about here in the southeast) is that they need major work to remain competitive. Our rail system stinks as well.
On the leadership side I am hard pressed to remember that last group of officials from any party that I could call statesmen. There is too much ideology and grandstanding. They debate insignificant issues while the major financial ssues we are facing continue to pound away at our long term solvency.
I would like to remain hopeful that we will overcome these issues but I fear for the burden my children and grandchildren will face at the rate we are going now.