Anthony is wholly incorrect that there is zero chance of America defaulting, that's not a forecast, that's an observation. Recall how very very close the US came to defaulting under Clinton, when they could not get a budget passed. That's not so long ago, and given that the US has an even more partisan political setup now, not so unlikely.
The idea that any state is permanent, is of course naive. Go read any history book and you will quickly spot that they come and go. America may often think of itself as a 'new' country, but is in fact nearly the oldest in the world. That speaks well of it's stability, but the mean time between failure of countries is <50 years. The USA has managed 234, when you have a mean of 50, which tends to zero by 250, do your own maths on how likely it is that any state can be 100% reliable over (say) 10 years. Obviously the odds of the USA defaulting in 10 years are small, but far from zero either. >10 years the numbers go up quite hard, pensions/demographics look vicious.
BBW is right, we could have a period where there is no dominant currency, it's not that unlikely either. I can't get my head around whether that is good or bad.
I then read Anthony's rather parochial analysis of the USAs strengths, which are mostly y wrong both in detail and in concept.
>1) The USA military is far from collapsing.
It's close to losing a war, that will have bad effects. The US military is of course huge, but that is both good and bad. You really really need to read up on how the US military went truly bad in the 1970s. It was bigger then than now, but had just lost a war. Not saying this will happen, saying it is not zero probability either.
[2) Countries are buying the dollar because we are transparent and it is safe.
Do you read any newspapers, or watch any TV other than Fox ? Even Fox would not agree with you on that. The US body politic is wholly corrupt. So corrupt that the strength of a politician is measured by the volume of bribes he has taken, and it is so corrupt that the politicians themselves publish the levels of cash taken to impress people. Some individual senators in the US have accepted more bribes in the guise of "contributions" than all three m ain British parties spent in the recent national elections, put together with about 2,500 candidates. In the UK an MP has been sent to prison for a dodgy expense claim of $20K, in the USA he'd get more bribes than that per day.
3) The USA has no "empire".
That's just so far from true, that I wonder at this point if I am making the mistake of responding to what was intended as a joke ?
Look at Korea, that's exactly the sort of strategic heel that did for the British empire, defending client states that were far away from the homeland.
Ditto Taiwan and Japan. If you look at the Pacific in general one sees a US Empire in all but name. Then there'e Puerto Rico, which although facing no real threats holds pretty much the same position in the US imperial system as Australia or Canada did under the British.
The USA has bases in >30 countries nearly as many as the British did at their peak.
The stated purpose of the Iraq and Afghan wars is to create "friendly states". The Romans, British, French and Swedes all did the same thing. I suspect that your understanding of history is so weak you don't even know the Swedes had an empire did you ?
A useful test for Imperial tendencies is if you go to war to defend a country that many of your population could not place on a map. Fighting to defend the homeland against invasion ain't imperial, but when you have to put a map on the screen to show journalists it's location, it is.
A war in Korea or Taiwan would be hugely expensive for the USA, both in money and men, utterly dwarfing the cost of both Moslem wars put together. It's been 40 years since the US has fought an enemy who could fight back. It's an open question how well it could cope.