McGrath,

Iraq has twice declared it would not sell oil to the US. The first time (April 2000-ish), they stopped selling. Economists declared a crisis. No crisis emerged. Iraq sold their oil to other consumers, and other producers sold us their oil.

The second time (November 2001-ish) was, apparently, a publicity stunt. Iraq declared (again) it would not sell the US oil (when it already wasn't) as a response to the attack on Afghanistan, stating that the attack on the country instead of just attacking the terrorists violated international law. (Which it did.)