No, it wasn't the "scream." It wasn't the "anger." Dean's fatal mistake on the night of his loss in Iowa was in not understanding who he was addressing when he spoke to that pep rally. He was talking to America, not the couple of hundred supporters in that room.
If he had used that moment to talk to the American people about why he was passionate in his quest, he could have turned it into a free commercial. Instead of thanking people for working on his campaign he could have made his case to the cameras - and the millions of people watching on TV.
Edwards seemed to understand this from the get-go. His speech that night was terrific. He was talking to the jury and not wasting a minute. Last nite Kerry was careful not to give Edwards a chance to make his case - he went in front of the cameras as soon as Edwards started to speak. Poor old Dean used half his time in the spotlight to thank his workers again. I would have thought by now he'd have figured out the game.
Dean was the best candidate but he wasn't smart enough in his use of the media.