Selzer: There's a chance they were blinded to what the Obama campaign was doing who basically said if we go to likely people who have caucused before we lose, we have to go and create a new coalition of people. It's a lot of work but if we don't win Iowa we're done. 

(music)

Hillary Clinton: Are you ready to end the war in Iraq and bring our troops home? Well, then let me ask you, are you ready to caucus tomorrow night to put us on a path to picking a president to get that done?

Obama: There's no shortage of bitter partisanship. We don't need more heat, we need more light. 

Yeah, it seems like double what we had four years ago. 

Henderson: It looks like 80,000 new voter registrants were signed up on caucus night 2008. That is an amazing number. 

Hillary Clinton's campaign had reached a caucus total that could have won on a regular democratic night in Iowa, except Barack Obama had done the seemingly impossible, bringing an unprecedented surge of first-time voters and independents behind him. The moment would forever change American history. 

Obama: On this January night, at this defining moment in history, you have done what the cynics said we couldn't do. 

Selzer: To me it was a statement about how blinded campaign can get in deciding who they think are likely to caucus and they're focusing all their resources on that and they'd be taken by surprise by somebody who has decided to go out and change the game.