"The USD is backed by the military and economic power of the USA which has never defaulted on its debt." @Skol
It is my view that no such supports for the USD are actually required. The underlying strength of the US dollar is structural.
It is a simple fact that all taxes paid to US governments - federal, state and municipal - are paid in US dollars. It is expected that these taxes will amount $6.7 trillion in 2018. US tax payers will need $6.7 trillion in 2018, and acquiring them is not an option. US governments don't accept Euros, gold or Bitcoin.
So to meet these obligations, US tax payers will either have to earn the US dollars or buy them.
Demand on this scale for this one requirement alone (there are plenty of other things that people need US dollars for) should make predictions for a collapsing US dollar look bit silly by itself.
