Generous Oil Companies and the Price of Gasoline?

When oil prices shot up after Hurricane Katrina, Congress summoned oil executives to Capitol Hill to give them a very public dressing down. The assumption seemed to be that oil companies could make prices rise at will. Now that oil prices are falling rapidly, will Congress invite those executives back to thank them? After all, if oil executives can control prices, then they’re being very generous right now.

Or could it be that oil prices result from supply and demand, and the post-Katrina hearings were a publicity stunt?