US federal debt
Most analyses of US federal debt, now trending upwards of US$15T, contain too much economism and fail tests of good fundamental analysis. Power relations underlie and determine all so-called money relations and certainly central bank/currency politics.
In all questions of whether the US debt to GDP ratio or absolute debt or sovereign default is at issue, consider confidence in the US society and infrastructure and natural capital, the economy which merely models and presents all this as finance. What factors increase and decrease this, and thus the potential regret of US investment?
"Isn't the US far more likely to inspire confidence with investment in upgrades to its transport, health care and energy systems, than it would be if these investments were not made. What's the yield of a trillion dollars spent on high speed rail, worker health, or a smart grid? Obviously creditor nations believe these are good investments OR THEY WOULD NOT BE MAKING THEM, THEMSELVES. So the real risk is to whine about numbers and not upgrade to USA 2.0." - Craig Hubley
Technically, the US can always just print all the money it wants and depress its currency using hyperinflation to wipe out its debt. Americans would pay much more for goods from China and oil from Canada that are presently much undervalued anyway, especially considering carbon footprint.
Bankers fear a US bankruptcy (euphemistically called a sovereign default) as it would clear the balance sheets. This would get many of them fired, but it would not break the banking system as a whole, just force major change that is already happening (see TEEB and natural capital for more on that.)