United States' public debt amounts to 6,998 billions of US Dollars, the 78.56 per cent of the US Dollar circulating monetary mass (M3), which is 8,807 billions of US Dollars. The public debt of the Countries of the Euro zone is 3,795 billions of Euro, par to the 61.86 per cent of the Euro circulating monetary mass, which is 6,134 billions of Euro. The ratio between 78.56 and 61.86 is equal to 1.2699, which is the same as the exchange rate between Dollar and Euro. Who's going to pay the public debts? The answer is easy: who detains Dollars and Euro.