KEY POINTS:
They call it the Clinton cackle.
It comes out of the blue, lasts a few seconds and leaves those who witnessed it wondering if they have missed a joke.
Hillary Clinton's deployment of the full belly laugh is the latest weapon used by the leading Democratic presidential candidate when she is being pummelled by reporters or rivals.
Friends say the cackle is her way of deflecting aggressive questioning.
It may also be a sign of nervousness over Iowa, where she is now running second to Barak Obama, according to one weekend poll.
Hillary Clinton still leads comfortably in the national polls over her closest Democratic rivals n Mr Obama and John Edwards.
But Iowa is the first bellwether state in the race, where the first major event in the nomination process occurs in early January followed immediately by the New Hampshire primary.
Defeat in Iowa would be a serious blow and may explain why Clinton is using humour to deflect criticism rather than the withering ripostes she is known for.
Mrs Clinton's friends say she has a terrific sense of humour. But her sarcastic tendencies do not go down well with Mid Western voters.
So she has turned to laughter.
When attacked about her many flip-flops - she voted for war in Iraq but now opposes it and she opposed universal healthcare but now wants it - she now bursts out laughing.
Conservative radio hosts routinely play Hillary Clinton's "cackle" on their radio shows and her enemy Dick Morris says it is "loud, inappropriate, and mirthless...
a scary sound that was somewhere between a cackle and a screech."The questions about her judgement are coming thick and heavy.
This week there will be more as her adversary Mr Obama tours Iowa to mark the fifth anniversary of a speech he gave opposing the war in Iraq.
Even Bill Clinton seems nervous about Mr Obama and said publicly last week that he was too inexperienced to run for the White House.
Mr Obama's ability to persuade the country that he has both good judgement and experience could now be key.
His deliberately non-confrontational style of campaigning is showing signs of working, at least in Iowa, where Newsweek says he is leading the Democratic field among those expected to attend the caucus 'meeting of neighbours' to decide the candidate.
Victory here would be a huge boost to the Obama campaign, energising his support across the country and upending the predictions that Hillary Clinton has the nomination all but sewn up.
Mr Obama is also raising more money than Mrs Clinton - more than US$75m over the past nine months - as ordinary people rather than wealthy donors eagerly contribute $10 and $20 a person through his campaign website.
Mr Obama's advisers express confidence that he will do well in both Iowa and New Hampshire and surge to victory a few weeks later when many states vote in what is being called Super Duper Tuesday.
His quiet-spoken style of electioneering has led many in the media to write off his campaign.
And while he has sharpened his criticisms of Hillary Clinton he still refuses to engage in an all-out assault on the former first lady.
"I know there's a tremendous blood lust out there in the political community who want us to be in a steel-cage match with her," said his chief strategist David Axelrod.
"Barack Obama didn't get in this race to tear Hillary Clinton down or to tear anybody else down. He got into the race to lift the country up. No doubt we have differences, and he will draw on those differences. But he is going to resist the thirst for gratuitous combat, because that's part of his critique of the political process."
As he takes his unorthodox campaigns to the schoolrooms and community halls of Iowa this week, Mr Obama is falling back on the oldest and most reliable trick in the book - pitting himself as very much an outsider against the Washington elites who have brought the country to its current impasse.
- INDEPENDENT
