Capitol Hill… created the conditions for this mess last summer with its latest energy bill. That legislation contained a sop to Midwest corn farmers in the form of a huge new ethanol mandate that began this year and requires drivers to consume 7.5 billion gallons a year by 2012. At the same time, Congress refused to include liability protection for producers of MTBE, a rival oxygen fuel-additive that has become a tort lawyer target. So MTBE makers are pulling out, ethanol makers can’t make up the difference quickly enough, and gas supplies are getting squeezed....