All it takes nowadays to drive crude oil futures up by a buck and a half is a minor kidnapping in Nigeria. Well, that and outages at a US oil refinery. The oil markets are now very sensitive to changes in supply, or even the most insignificant threats to that supply. Thus, the importance of a letter from Ahmadinejad (and its rebuff by Rice and Bush), and of the rising unrest in the Niger Delta over environmental and political justice, where production has already been cut by 25%.
Add to this the now rampant speculation about President Obasanjo's efforts to change the constitution to permit him a third term (Obasanjo and all other credible candidates are former generals), and ... well, let's just say that I'd start buying summer through winter delivery futures now.