US:New polls suggest that voter turnout will determine the outcome of a tight, three-way Democratic presidential contest in Iowa, while Republican Mike Huckabee has moved to the front of his party's field nationally, writes Denis Stauntonin Washington.
As Hillary Clinton, Barack Obama and John Edwards focus almost all their resources on Iowa in advance of the January 3rd caucuses, an ABC News/Washington Post poll put Mr Obama at 33 per cent, four points ahead of Mrs Clinton, leaving Mr Edwards trailing at 20 per cent.
Mrs Clinton has been advancing her softer side on a five-day tour of the state this week, which has included testimonials from childhood friends and people whose lives were affected by the former first lady's work on behalf of children.
"I know that people have been saying, 'Well, you know, we've got to know more about her, we want to know more about her personally.' And I totally get that. It's a little hard for me. It's not easy for me to talk about myself," Mrs Clinton said during an appearance with her husband Bill, and former basketball star and Aids activist Magic Johnson.
For his part, Mr Obama has been hardening his message, making fewer references to hope and emphasising his hard-nosed political experience in Illinois and in the US Senate.
Mr Edwards, who spent months sniping at Mrs Clinton, has returned to his avuncular, sunny persona of 2004, when he came in second in Iowa.
One in three likely caucus-goers say they could yet change their minds and one in five say there is a good chance they will do so. The latest poll has good news for Mr Obama, whose supporters are more likely to say they will definitely show up to caucus. The Illinois senator also fares best in second preferences from candidates who are likely to be eliminated because they receive less than 15 per cent in the first round of voting.
The poll found, however, that more of Mrs Clinton's supporters than Mr Obama's say they will not change their minds and that they are "very enthusiastic" about their candidate.
Another poll showed Mrs Clinton regaining her lead over Mr Obama in New Hampshire, which holds the first primary on January 8th.
On the Republican side, Mr Huckabee enjoys a comfortable lead over former Massachusetts governor Mitt Romney in Iowa and a new Reuters/Zogby poll shows Mr Huckabee tied in first place nationally with former New York mayor Rudy Giuliani.
The former governor of Arkansas closed an 18-point gap in one month to pull within one point of Mr Giuliani. Mr Huckabee's rise has added uncertainty to a confused Republican race, where Mr Romney continues to enjoy a big lead in Iowa, although John McCain's campaign has started to revive and Mr Giuliani remains strong nationally.
Mr Romney has started running attack adverts against Mr Huckabee in Iowa, accusing the Arkansan of being soft on crime and too eager to raise taxes. Mr Huckabee's latest advert contains no overt political message but wishes voters a merry Christmas, reminding them of the religious nature of the holiday.
An ordained Baptist minister, Mr Huckabee described himself as a "Christian leader" in an earlier advert and some commentators have remarked on the fact that a bookcase behind him in the latest commercial looks remarkably like a cross. A Rolling Stones fan who plays guitar, Mr Huckabee laughed off the suggestion of subliminal messaging with a reference to an old controversy about a Beatles' song. "I will confess this: If you play the spot backwards it says 'Paul is dead, Paul is dead, Paul is dead'. "