Candidates are using the first day of 2008 to make last-minute appeals to the undecided voters of Iowa.
Fresh polls are showing both races too close to call, and that's why Republican and Democratic presidential hopefuls are rolling out upbeat television ads and packing their schedules with multiple campaign events.
Hillary Rodham Clinton's campaign is emphasizing a CNN poll that shows her slightly ahead. But Barack Obama, shown ahead in a Des Moines Register poll, told supporters Tuesday in Des Moines he is on the brink of "doing something very, very special" on Thursday.
On the Republican side, Mike Huckabee, who is in a close race with Mitt Romney in Iowa, is back out campaigning after deciding to show a negative ad to the media instead of putting it on the air.