Oil can be bought from OPEC only if you have dollars. Non-oil producing countries, such as most underdeveloped countries and Japan, first have to sell their goods to earn dollars with which they can purchase oil. If they cannot earn enough dollars, then they have to borrow dollars from the WB/IMF, which have to be paid back, with interest, in dollars. This creates a great demand for dollars outside the U.S. In contrast, the U.S. only has to print dollar bills in exchange for goods. Even for its own oil imports, the U.S. can print dollar bills without exporting or selling its goods. For instance, in 2003 the current U.S. account deficit and external debt has been running at more than $500 billion. Put in simple terms, the U.S. will receive $500 billion more in goods and services from other countries than it will provide them. The imported goods are paid by printing dollar bills, i.e., "fiat" dollars.
Why are we in Afghanistan and Iraq and, soon, Iran?
Here is a persuasive shortish paper outlining the probable real reasons, also meanwhile explaining why our McEconomy, such as it is, is still propped up. In a country with a media that wasn't dominated by corporate interests, articles like this would be in the paper. Get them on the Web while you can! A snippet: