Biden Says Iowa or Bust

ABC News’ Tahman Bradley Reports: Sen. Joe Biden says he must finish in the top three in Iowa to continue his presidential campaign.

Radio Iowa’s Kay Henderson reports that Biden conceded in an interview that "anything less than a first, second or third place showing for him on Caucus Night will spell the end of his presidential campaign."

Read the interview here: http://www.radioiowa.com/gestalt/go.cfm?objectid=88BBCB79-CA33-C7EE-220B0EE9DB02C19F

The Delaware Democrat, who polls in the single digits in the nation’s first caucus contest, predicted a lesser-know candidate will push ahead of top Democratic candidates Barack Obama, Hillary Clinton and John Edwards.

"I think one of us is going to end up supplanting one of the so-called top tier candidates," Biden said in the interview.

In the latest ABC News Washington Post poll, Biden lagged behind the leading Democratic candidates by nearly 25 points.