Up in the polls one week, down the next. That seems to be the experience of every presidential hopeful at the moment. The voters in Iowa are undecided. No candidate can be sure of winning. The primary election on 3 January will be a nail-biter.

From CNN's "Political Ticker":

Clinton and Obama were neck-and-neck in last week’s American Research Group poll. But in the new survey, conducted December 20-23, she leads the Illinois senator by 15 percentage points, 34 to 19 percent. Obama is now in a statistical tie for second place with former North Carolina senator John Edwards, who has 20 percent of the vote.

And:

A week ago, an ARG poll placed Mike Huckabee over Mitt Romney by an 11-point margin among likely Republican caucus-goers, but the latest poll by the group puts the two back in a statistical tie, 23 to 21 percent. John McCain has 17 percent of the vote, Rudy Giuliani has 14 percent—and Ron Paul has 10 percent in the latest poll, up from 4 percent last week.