Allow me to simply interject that the USD retains some semblance of importance due to agreements with several OPEC countries that require they price their oil for international sales in USD. Countries can buy our debt, priced in dollars, and can (Not that they do, but they can...) exchange that debt for oil. The dollar is backed by oil, and we use our military to keep it that way. Iraq switched over to pricing their oil in Euros in 2000. Three years later, we occupied their country, and the new leadership prices their oil in USD. The other major oil producers that price in Euros? Venezuela and Iran, both countries that could be said to have increasing tensions with the US.
I'm not about to speculate what is or isn't in Ft Knox, because really it doesn't matter. The US has been doing for years now what the rest of the world is just waking up to, and thats keeping the gold wealth inside it's borders not by hoarding it in a safe, but letting the public buy and sell it. Thats where the true measure of the value comes from. Look at China. It encourages it's citizens to buy as much gold as it can. It doesn't build a giant vault into the ground to preserve it for no reason. It uses it to boost it's rating as an investment and an asset. So, what good would it do anyone or any government if Ft Knox were sitting filled to the brim with gold that nobody could touch? Guy