Let's try a political thought experiment. Imagine that a few months after a new president takes office, his administration approves an offshore oil well a mile beneath the Gulf of Mexico. It is to be run by BP, whose employees were very generous donors to the president's campaign. The oil company airily dismisses the possibility of a catastrophic leak that might destroy the coastline. Nearly a year later, the president—to the dismay of his environmentalist supporters—says he wants to greatly expand offshore drilling. Soon after that, the BP well explodes, and oil spews into the gulf. It's clear to everyone...
