Well, there is plenty of material on the federal reserves. The capability of the dollar to be so untouchable is because of that.
And to the fact that a currency is only stable as long as the country is: Well, I would say that 80% of the world population has experienced radical changes to their currencies and assets (inflation, complete devaluation, rebranding, coupling to other currencies, stock market crashes, ...) within their lifetime (for whatever reasons). Having a multi-generation-stable currency is the privilege of only a very few countries like the US, Canada, France or Germany. Looking at the history of a country will easily reveal a significant event in the last 50 years which included something destabilizing.
Even the mighty UK was crashed by a single investor (the infamous George Soros).
And again, my argument is limited to the following element: currency stability > country stability.
