Long term, our government can either default on its debt (I doubt this will happen) or use massive inflation to reduce the effects of debt (this is what I think will happen).
I think that it is impossible to predict when this will occur and whether it will be rapid (hope not!) or gradual (my hope).
Both W. Bush and Obama spent way too much money on credit. If you as an individual are going to to buy a car for $20K and pay for it over a 5 year period, you should not say "this car cost me $20K," rather, it is really more accurate to say "this car is costing me about $28K with interest." It would be nice, but unexpected, if instead of the government saying "we are going to spend $500 billion on defense this year" they would be more honest and say "defense spending this year, including interest on the money spent, is estimated to be between $1 trillion and $1.5 trillion."
Doesn't that sound a bit more honest?