We've had debts this large before, at least as a percentage of the GDP, and neither debased the currency nor defaulted. Sooner or later we will get to the point where we'll have to do one or the other, but we're not there yet.
We haven't debased the currency? Are you sure? Does a dollar buy the equivalent amount that it did in 1960? Inflation, or ongoing debasement, is a way to decrease the accumulated wealth stored in account balances. It also devalues longterm debt, too. For instance, the payments made on the tail end of a 30-year note have usually been a lot easier to earn than the ones made at the beginning of the loan. Cost-of-living raises over the entire period have usually ensured that.
I suppose you could say that whether or not we can pay it off depends more on what the future of our economy actually turns out to be. Since we were gravitating towards a "service economy", we haven't needed to manufacture as much, right? So... what, exactly, is a "service economy"? In the worst case, I do your laundry and you do mine! Doesn't look like that'd really work, does it? Of course not. So... what else could it mean? Financial services? Uhh... kinda' looks like the rest of the world's not currently in the best shape to make much use of that, does it? Iceland put just about all their eggs in one basket as a financial services economy and look where it just got them!
Bottom line... as long as you've got plenty of your own energy and resources (mineral and agriculturual), you're fine--you've got something to trade with the world in return for what you need. Oops... we seem to need more than we have to trade... And, yes, that has definitely changed over these last few decades since our own oil production began to drop after it hit
Hubbert's Peak. Remember the energy crisis of the '70s? We'd have languished then if it hadn't been for
Kissinger convincing the oil states to trade oil in US dollars.
The most horrible thing that can happen to us is if they eventually decide to start trading oil in Euros or SDRs. Anybody with any real sense understands this. Rumblings toward that direction have been going on for years now... take a quick gander here:
http://www.888webtoday.com/joyce8.html
That was a few months after 9/11. Today, it's China and a few others who are pushing the deal.
Okay... so... what happens if the world dumps the dollar as a reserve currency? Well, I guess you could say that we would then only be able to trade tit-for-tat, which would be a huge drop in our standard of living. Could we ramp up our own internal resource and energy production? In time to stave off disaster? No way. The same people who push the idea that that's too pessimistic of a view also happen to be the people who: 1) Can't run a calculator to save their lives; and, 2) Don't have either a lick of common sense or adequate knowledge of the subject.
Naturally, we aren't completely doomed as a country--we're not all going to be dying tomorrow of starvation. What it really means is that the idea of continued growth and a whole plethora of increasing benefits for the common man as we proceed to a Star Trek utopian society... is rather unlikely. I'm not going to blame that on the current administration, nor am I going to blame that on the last one--I'm going to blame that on simple realities that we cannot control. If it comes true as I've expressed it... who should we blame? And why? Didn't we ALL mostly consume the resources? Didn't we ALL mostly keep having more kids? Didn't we ALL help create a country that was so desirable to live in that other folks from all over wanted to come here and also enjoy it? In spades?
Oh, yeah... there's an awful lot to that entire debate, so much BS floating around, in fact, that nothing of it's an absolute certainty... probably most of which was thought up in order to support the concept that it's always "somebody else's fault". Them.