Some economists were actually afraid that the US would entirely free of debt by now, suggesting in this 2000 report  that such an achievement could be a bad thing:

We must realize however, that a sharp reduction in Federal debt and the possible accumulation of a Federal asset raises at least three important issues. First, investors looking for an asset free of credit risk can no longer count on an abundant supply of U.S. Treasury securities, and Treasury securities may no longer provide a reliable benchmark for other interest rates. Second, the Federal Reserve may have to change the mechanisms by which it conducts monetary policy. Third, continued surpluses after the public debt has been paid off will require the Federal. government to acquire assets; either directly or though the Social Security Trust Fund.

Although the right wing assures us on the hour that everything is Obama’s fault, I really think we should do some sort of ceremony to thank George W. Bush and his Big Dick for eight years of dedicated efforts to make sure we will probably never run that risk again in our lifetimes. We just didn’t appreciate them enough while we had them.