AP

Republican hopeful Mike Huckabee speaks at a restaurant in Mason City, Iowa.

DES MOINES , Iowa — We're one day away from the Iowa caucuses, and that means the candidates for president have some last-minute campaining to do in a race that looks wide open.

This is the most unpredictable presidential race in more than 50 years. One day before the voting starts, we have no idea who the two party's nominees will be.

It's safe to say Iowans have never seen anything like this. Celebrities like Oprah Winfrey have been campaigning for... Democrat Barack Obama.

Hillary Clinton has celebrity backers, too, including basketball's Magic Johnson—and, of course, her husband, the former president.

Celebrities are not John Edwards' calling card. Four years ago, the Democratic candidate finished a strong second to John Kerry in Iowa.

"John Edwards, we have to remember, never really left after the '04 caucus cycle," said Drake University political analyst Dennis Goldford. "He had a good, strong organization here in Iowa."

Edwards talks a lot about the economy, and so does Republican Mike Huckabee. Polls show the Baptist minister and former Arkansas Governor in a close race with former Masachusetts Gov. Mitt Romney.

As caucus day approaches, records show that Romney has spent $4 million on TV ads in Iowa, compared with just $220,000 for Huckabee.

"Can the volunteer network, the volunteer support of a Mike Huckabee—can it really overcome a paid staff, well-oiled machine that Mitt Romney has here in the state?" asked Huckabee campaign worker Bob Vander Plaats.

While most of the candidates will spend all day Wednesday campaigning in Iowa, Huckabee won't. He's flying to Los Angeles to appear on the "Tonight Show." He says if the caucuses don't work out, maybe Jay Leno needs a sidekick.

Huckabee has become the favorite of Christian conservatives in Iowa. Even though the leaders of some religious right groups backed other candidates, Huckabee's winning the hearts of people like parents of home schoolers.

And they may be more motivated to turn out than some other people.

The economy is also a big issue in Iowa, where—like a lot of other Midwestern states—many of its manufacturing jobs have moved overseas.

The state's farm economy is booming, however, because of the demand for corn being used to produce ethanol fuel.

If both Edwards and Huckabee do well in Thursday's caucuses, concerns about the economy could be the reason.