The problems with a one world currency

The Washington Times has this piece:

The Group of 20 gave a nod to the idea of a single world currency last week, and other countries such as China are pushing it because they no longer trust the United States to restrain itself from printing too much cash and debasing the dollar. While we share China's concerns about the danger of Washington over-printing money, there are numerous reasons to avoid a global currency. . . . .