Once people lose confidence in paper, which is what is happening in Japan right now, the confidence isn't gained back easily. Over the weekend, a relative gave me more than 200 German 100-mark notes issued between 1903 and 1910. When issued, they were worth just under $25 -- i.e., more than an ounce of gold. I was recently appraised that they are now worth between $0 and $0.07. They were demonetized following the German inflation of 1923.
American policy makers tend to boost American economy by lowering the saving's rate and making credits cheaper. It works up to a certain point. But the temptation to overdo it is too great. It is like a potent stimulant. One can always come up with some scenario where growing debts and other problems can be taken care of. But its plausibility will go down as time goes and more of these problems continues. We will see how this will turn out. In the end, somebody has to pay up all these. The easiest way is to socialize (or monetize) debts and blame it on small selected group of convenient scapegoats.
U.S. is different from Japan. But that difference is not wide enough to ensure that America escapes with minor damage to its economy and Japan goes down big time. The difference is in my view that America decided to pump in money(credits) before bubble pops like Japan did. So America is forestalling the popping for now. And America may monetize debts rather than going under like Japan.
After WWI, the French forced a debt burden on Germany they couldn't pay that led to their hyper-inflation. The French were also the ones in the early 1970's who pushed the United States to default on its gold debt under the Bretton Woods foreign exchange system. If you think the United States is going to default on its payments again, let's hear your reason, rather than your emotion based dislike of our fiat currency.