Candidates Make Final Push Before First Real Nominee Tests

The Iowa caucus will be held Jan. 3, throughout the state. The next big test is the New Hampshire primary, held five days later.

The two events kick off a month-long period packed with state caucuses and primaries, culminating with a record 22 states casting presidential primary ballots on Feb. 5.

But to be viable in February, experts say a candidate has to finish in the top three in either Iowa or New Hampshire.

Iowa has a long tradition of being the first test for presidential candidates. According to state law, the Iowa caucus must be held eight days prior to the New Hampshire primary. And New Hampshire law states that its primary must be held a week before any other primary.

Caucus vs. primary

	The 2008 race for the White Housebegins in Iowa and New Hampshire.

On the evening of the Iowa caucus, citizens will line up to register for either a Democratic or Republican caucus. These are small, informal, town hall meetings in homes, schools and other public places. Delegates are chosen through a variety of methods including pen and paper tallies, a show of hands or a straw poll. The process can take many hours.

In New Hampshire, voters show up at a polling place and cast private ballots.

Rules for primaries and caucuses vary by state. Each state party uses its own rules for delegate selection, but those rules are subject to approval by the Republican National Committee or the Democratic National Committee and the state's election law. Usually, the state's legislature decides on the date and format for the primary or caucus.

The candidates

	Democrats Hillary Clinton and Barack Obama are in the hunt for a win in the Iowa caucus.

Among the Democrats there are three front-runners: Sen. Hillary Rodham Clinton of New York, Sen. Barack Obama of Illinois and former Sen. John Edwards of North Carolina.

These three Democrats have all had jostled for top status in the Iowa polls leading up to the caucus.

"It seems there's a rotation among them," David R. Nagle, a former congressman and past chairman of the Iowa Democratic Party, told the Los Angeles Times. "One will have a good day and seem to surge ahead, then another will have a good day, and then another. They seem to reach a plateau and no one can break away from anyone else."

A clear front-runner is not yet apparent in Iowa for the Republicans. Former Gov. Mike Huckabee of Arkansas has recently surged into the top two in the state against former Gov. Mitt Romney of Massachusetts. The battle for third is up in the air.

Why voters choose a candidate

	Former Ark. Gov. Mike Huckabee has surged to the front of the Republican race in Iowa.

"So all of these candidates bring in some strengths and weaknesses that they know the other side is going to use against them in November. And they're trying to judge which one of these has the best package of good strengths and weaknesses that aren't so troubling," Andy Smith, professor of political science at the University of New Hampshire and director of the university's survey center, told the NewsHour.

And unlike in past presidential elections, single issue determiners - like the way a candidate falls on the abortion or gay marriage debate - seem less important than the ability a candidate has to run a complex job like the presidency, according to some analysts.

"These things have really nothing to do with running the country. And so those issues have really sort of, I think, played a little bit less, as people are really thinking about the complex world that the next president will inherit," Ann Selzer, who directs the Iowa poll for the Des Moines Register newspaper, told the NewsHour.