But on the town hall stage on Monday, she pushed back at Sanders' judgment argument by evoking Obama, who remains popular with Democratic voters and was critical of her Iraq War vote when the two competed in 2008.

Clinton's support among likely Democratic primary voters has dropped to 49 percent, according to a Fox News poll released Monday evening.

Calling the meeting "constructive and productive", Sanders cautiously praised the Obama administration's economic work, saying there is still work to be done.

Clinton was more animated than usual, raising her voice to make points, and Sanders made the audience laugh with some jokes.

FiveThirtyEight, which utilizes factors beyond polls in its "polls-plus" predictions, actually increased Hillary Clinton's Iowa chances to 79 percent, though it's still off the 85 she carried for most of the month and hasn't factored in the Quinnipiac poll.

The mobilization of his young army of admirers will help determine whether he's able to slow - or stop - Hillary Clinton's march to the Democratic presidential nomination. At the moment, the FiveThirtyEight data site's prediction for the Iowa caucuses, based on polls and other data such as endorsements and money, gives Clinton a 79 percent chance of Iowa victory, and Sanders a 21 percent chance.

Her number one priority, she says, is improving incomes.

Sanders' campaign has indicated that the 74-year-old does not want to take part in an additional debate. Clinton responded later with little of the feistiness she has shown recently on the campaign trail, instead reverting to her earlier posture of confident front-runner, emphasizing her qualifications for the office and trying to avoid engaging her rivals. While the questions she faced where less specific on policy, she emphasized that the tough challenges a president faces - an implicit suggestion that Sanders is proposing unrealistic ideas.

"I've been on the front lines of change and progress since I was your age", Clinton said. Clinton was referring to the news that Joe Ricketts, a major Republican donor, is funding a super-PAC to air ads in Iowa that could serve to bolster Sanders' caucus bid by describing him as "too liberal".

"I think it's fair to say I have a 40-year record in going after inequality", said Clinton, adding that she's also fought inequality on the basis of race, gender and sexual orientation.

"We have some fairly sophisticated people who know about the caucus process here in Iowa", he said Tuesday.

"We will win here in Iowa if the voter turnout is high and frankly if the voter turnout is not high we're going to be struggling", he said. "I think Bernie came in with the luxury of being a complete long-shot and just letting loose".