Can Clinton play ‘a carom shot’?

How much will Martin O'Malley's showing on Monday help the presidential progress of Hillary Clinton or Bernie Sanders? Will college students show up?

That's just one of several factors that will determine what happens at Iowa's Democratic caucuses Monday evening. But interviews with several veteran political analysts across the state have identified some common themes.

Here are five keys to the caucus:

1. Martin O'Malley

You can't find too many Democrats who don't like Martin O'Malley. But public opinion polls haven't found too many willing to vote for him.

On average, O'Malley is polling about 5 percent — far below the 15 percent viability threshold he'll need in each precinct to qualify for delegates in the Democratic caucuses.

So what then happens to his supporters if he doesn't establish viability?

In a tight race, it could be important factor.

'If they all go to one place, that can have a big impact,' said Norm Sterzenbach, a former executive director of the Iowa Democratic Party.

In 2004, John Edwards and Dennis Kucinich cut a deal to help the other in case they weren't viable in a precinct.

In 2008, there were plenty of stories about Barack Obama supporters shifting to help other campaigns to keep Hillary Clinton from getting delegates, which is what determines the winner in the caucuses. More on that later.

'I call that a carom shot,' said Kurt Meyer, chairman of a three-county Democratic Party organization in northern Iowa, 'and I think Mrs. Clinton has learned how to play these carom shots.'

2. College support

It's well known that polling says Bernie Sanders is doing better than Hillary Clinton with Iowa's young people. But there are limits to that support.

A Des Moines Register poll this month said 27 percent of Sanders's support in Iowa came from Johnson, Blackhawk and Story counties, home to Iowa's three state universities. But those counties get only 21 percent of the state's 'delegate equivalents,' which is what counts in a caucus.

Individual voters determine how many delegate equivalents go to a candidate. But because of the way delegates are apportioned across the state, it isn't always a one-to-one ratio.

'Diffuse support is better than concentrated support in a caucus state,' said Dave Nagle, a former congressman and party chairman.

And unlike past caucuses, college classes are now in session, meaning students are spread across the state. There are varying opinions on how big a factor this might be. Sterzenbach thinks it's a big deal.

'That's going to have a really big impact on the outcome,' he said last week.

But Donna Hoffman, chairwoman of the political-science department at the University of Northern Iowa, doesn't see it as that pivotal.

'He's been doing events all over the place,' she said of Sanders.

Still, the Sanders campaign is addressing the issue. It has launched a 'Go home for Bernie' initiative to drive students back to their hometowns to caucus for Sanders.

It's not clear how effective that might be. But consider this, too: Out-of-state students who are in Iowa for classes, rather than back home on break, also can caucus Monday. That could blunt whatever impact there is on Sanders.

3. Will the system work?

The 2012 Republican caucuses won unwelcome notoriety by declaring Mitt Romney the winner at first, but later reversed course when an audit discovered Rick Santorum got the most votes.

In addition, the precinct caucus results didn't reflect who got the state's delegates at the national convention. In 2008, the Democrats also were challenged by a large turnout.

The parties have taken great care to improve the system and improve inclusiveness. The results in Monday's Republican caucus now will be tied to delegate counts.

In addition, both parties have moved to try to stanch questions about participation, which typically is low. The Democrats have created satellite sites and tele-caucusing, while Republicans have promoted a military caucus for those who can't be in Iowa on Monday.

Iowa's first-in-the-nation status already has plenty of critics, so how the caucuses are run Monday night will be closely watched.

Campaigns have spent millions of dollars here. Thousands of campaign workers and media are on the ground.

'And all this is poured into a vessel that is volunteer-built and volunteer-maintained,' Meyer said.

It's the parties, fueled by volunteers, that administer the caucuses, not state election officials. And in an era of social media, flaws can be magnified.

Both parties say they're up to the task.

4. Turnout

Saying the winner of the caucuses is dependent on who turns out to vote is a little bit like saying the winner of a baseball game depends on who scores the most runs.

Well, duh.

But it may be the biggest question mark going into Monday.

The campaigns can organize, but in the end, turnout generally amounts to a fraction of registered voters. So determining how many there are and who they will be is not just what makes polling Iowa so hard — it's also why campaigns spend so much money trying to figure out who will show up.

Sanders has argued a bigger turnout helps him. Polls say Clinton gets more loyalty from party veterans, who are more regular caucusgoers.

Most experts suggest Monday's overall turnout likely won't match the bin-busting 2008 total of 240,000. But where the number does fall is a bit of a guessing game — more hunch than science — for outsiders.

In 2004, about 125,000 turned out — a total Sterzenbach believes is reasonable to expect this year, too. Nagle thinks it will be higher, perhaps even 200,000.

5. Expectations

More than 40 years of the Iowa caucuses have proved the winner isn't always the winner. And coming in second isn't necessarily a bad thing.

In 1976, 'uncommitted' got more delegates than Jimmy Carter, but Carter, the eventual party nominee, got the headline.

In 1996, Bob Dole won Iowa, but Pat Buchanan ran a strong second — stronger than expected — so he got a bounce out of Iowa and ended up winning New Hampshire, too — although not the nomination.

The national media plays a huge role in all of this.

It's hard to know how Monday's results will play. The Republican National Committee tried to make the case last week that anything but a 'resounding' win for Clinton is a loss. But with the polls saying just a few points separate Sanders and Clinton in Iowa, that could have tamped down expectations for the former secretary of state.

'The expectation now is this is a very close race,' the UNI's Hoffman said.

Still, a year ago, Clinton led by huge margins — a fact Sanders has been emphasizing on the stump and in interviews with the media.

Even if Clinton wins, Hoffman said, the idea that she lost that big lead will 'probably be influential' in what's written in the days between Iowa and the New Hampshire primary, Feb. 9.