From accounting point of view, debt always equal to credit. A's debt is B's credit, if both A and B have credit (saving), then there must be some one in larger debt to balance. American government's debt could be balanced by surplus countries' credit.

In gold standard era, money was created by gold miners, it was possible that everyone have a credit (through saving). But in modern time, money is created by central banks, and they become the biggest debt taker, because their money is just created out of thin air, not by hard work. In this sense, money just act as exchange media and value benchmark, if central bank abuse this power for their personal interest, then they will destroy the credibility of the currency