Actually, they made this assertion about the United States and the United Kingdom, which makes considerably less sense than saying Bill Gates is broke. There is no evidence that either country is coming up against any sort of spending limit. The bond markets are willing to lend both governments at very low interest rates and there is certainly no shortage of people who are willing to accept the currency of the two countries.
Since it has no basis in fact, the Post's assertion that these countries are broke is presumably an expression of its unhappiness with how these governments spend their money. This is the sort of sentiment that newspapers are supposed to leave for the opinion pages.