So while Hillary and Barack were boxing each other's ears....

Johnny the Tortoise slipped quietly into the lead in Iowa (at least according to one poll):

John Edwards has leapfrogged over his rivals Hillary Clinton and Barack Obama, and leads the Democratic field in Iowa, according to the latest InsiderAdvantage/Majority Opinion poll. In the Republican caucus race, Mike Huckabee continues to hold a narrow lead over Mitt Romney.

The race among the three top Democrats is extremely close, with the potential for any of them to finish first – or third.

Edwards leads with 30 percent in a poll of Democratic voters who said they intend to participate in the Jan. 3 presidential caucuses, followed by Clinton with 26 percent and Obama with 24 percent. When the sample was narrowed to the most likely caucus-goers, based on several questions, Obama leads Edwards by less than a percentage point with 27 percent, with Clinton in third place at 24 percent.

Edwards holds a significant advantage, however, among a group who could be key to the first contest of the presidential year: those who say their first choice is someone other than the top three. Under Iowa Democratic Party rules, candidates who poll less than 15 percent in the first vote at each caucus around the state are eliminated, and their supporters get a second chance to vote for another candidate.

Under both screens, Edwards leads as the second choice of these voters, with Clinton trailing Obama.

“If Edwards is the second choice at this stage of those who intend to vote for other Democrats, then it would not be surprising if he produced a bit of a shock in Iowa,” said InsiderAdvantage CEO Matt Towery.

(h/t)