I don't think that America is a failed nation. You have to be more specific about the issue why you're calling it as a failure. America is still the strongest nation of the world, they are dominating every aspect of daily life.
So I don't agree with you on this point.
America is not a failed nation since it is still on the top of the financial system. But there are many obstacles that will somehow turn the world of America upside down and if they are not careful they will basically encounter and economic breakdown. But given the new president of the United States who is Trump an expert in economics and business surely these problems will be solved during his term.