The justices reached no firm conclusions in court Wednesday, but they appeared to agree with Exxon that the $2.5 billion - or $75,000 a person - ordered by a federal court is excessive punishment for the massive 1989 oil spill.
Two justices, who could hold the balance of power in this case, suggested a payout of about $1 billion might be appropriate.
There was little talk in court of the plight of Alaskans who depend on the area environment for their paychecks or of Exxon's run of record profits. Neither has much to do with the legal principles that underlie the case.
The award represents less than three weeks' worth of Exxon profit, which was $11.7 billion in the last three months of 2007.
Still, Exxon has vigorously fought to knock down or erase the punitive damages verdict by a jury in Alaska in 1994 for the accident that dumped 11 million gallons of oil into Prince William Sound. The environmental disaster fouled 1,200 miles of Alaskan coastline and led to the deaths of hundreds of thousands of seabirds and marine animals.
The verdict has been cut in half once by a federal appeals court.