The Supreme Court today agreed to decide whether Exxon Mobil Corp. should pay $2.5 billion in punitive damages in connection with the huge Exxon Valdez oil spill that fouled more than 1,200 miles of Alaskan coastline in 1989. The high court stepped into the long-running battle over the damages that Exxon Mobil owes in the spillage of 11 million gallons of oil into Alaska's Prince William Sound, the worst oil spill in American history. The Exxon Valdez supertanker had run aground on a reef. A federal appeals court already had cut in half the $5 billion in damages awarded by a jury in 1994. The justices said they would consider whether the company should have to pay any punitive damages at all. If the court decides some money is due, Exxon is arguing that $2.5 billion is excessive under laws governing shipping and prior high court decisions limiting punitive damages.