A long time ago, when oil first became popular, the Arab countries began accepting the US dollar for all their sales. (It didn't start being called the petrodollar until 1973.) That meant that if Japan wanted to buy a barrel of oil, it had to buy US dollars to do it with. This alone has kept the dollar afloat far longer than it would have naturally. As the value of the dollar dropped, starting with Nixon going off the gold standard in 1971, countries began to grinch privately that they weren't getting as much money for their oil as before.

Thus evolved petrodollar warfare. In 2000, Saddam Hussein began accepting Euros for oil instead of dollars. This was the real reason for the Iraq invasion. Now, Iran is threatening to do the same. Can another war be far behind?

But the truth is that if the petrodollar ceases to exist, America will crash. There will no longer be anything at all backing up the dollar and it will be worth less than toilet paper. So we can either collapse from the weight of debt needed to finance the wars or we can stop fighting and deal with the consequences a little sooner

http://www.bitsofnews.com/content/view/6352/