Gail: That is basically my read of things too. Increased imports of finished gasoline to the US have depressed prices here and put the hurts on domestic refiners. As I understand it, you can generally get more gasoline than diesel out of a barrel of oil, and the US consumes 43% of the world's gasoline, so we're basically the beneficiary of the rest of the world trying to refine a sufficient amount of diesel to power themselves. I wrote two articles addressing this, and much credit to Robert for my education along the way:
High Gasoline Prices Are Here to Stay and The Big Picture on Q2 2008, Part 1

I heard today that some of the US refineries have been trying to add cracking capability, so they have more flexibility in what they produce, but have had difficulty in getting the EPA to approve the changes. This leaves them tied with less flexibility.