Acting assistant attorney general Dan Levin apparently asked to be waterboarded when evaluating its legality, according to ABC News.
After the experience, Levin told White House officials that even though he knew he wouldn't die, he found the experience terrifying and thought that it clearly simulated drowning.
Levin, who refused to comment for this story, concluded waterboarding could be illegal torture unless performed in a highly limited way and with close supervision. And, sources told ABC News, he believed the Bush Administration had failed to offer clear guidelines for its use.
UPDATE: Marty Lederman has more thoughts on this story here.