Time Magazine: Every few years, government officials gather to prepare for the unthinkable. Back in April 2002, the Coast Guard held one such exercise, a three-day summit at the Louisiana Superdome in New Orleans. It was designed to simulate a response to an oil spill of “national significance.” The catalyst? A hypothetical explosion on an ExxonMobil platform off the coast of Morgan City, La., that sent 126,000 gal. of crude gushing into the Gulf of Mexico. The man in charge was a Coast Guard vice admiral …