America has been through doom and gloom before. Civil War and the Great Depression spring to mind. It will come back. Weaker than before since there are other rising world powers and economically it's not dominant like it is militarily but even militarily it's been challenged. It's having a tough time putting down the Taliban insurgency who are mostly armed with 40 year old Soviet weapons and have limited financing and this has hurt it's prestige.
What would really help is if Russia and China go to war and then they choose a side (probably Russia) a few years later and join the war. And then the side they picked would have to take out massive loans from the US to continue the war effort and rebuild and in exchange they would have to buy American. New Deal and Marshall Plan v.2 
