Coast Guard stumbles as it tries to preempt Massachusetts state law

The Massachusetts Oil Spill Prevention Act (OSPA) was enacted following an oil spill in Buzzards Bay. [As the appellate court notes, Buzzards Bay is a scenically beautiful body of water. See also http://en.wikipedia.org/wiki/File:Buzzards_Bay_map.png.] OSPA requires a tugboat escort for all tank vessels...