Screwing with the "petro-dollar" is supposedly what got Sadam overthrown. Sadam started only accepting Euros for his oil which severly threatened the foundation of our shake dollar reserve currency.

We placed bans on Iran selling their oil, but India (largest customer) isn't that much of an ally to give it up. Iran started accepting gold for its oil and that irked the US as well. T

Read up on the petro-dollar its fascinating (i'm in finance).

[link to en.wikipedia.org]