It will be a working and traveling weekend in Iowa for the Democrats running for president. Bernie Sanders is finding enthusiastic receptions in locations outside Des Moines, while Hillary Clinton drummed up support at Grand View University in Des Moines. Our Josh Robin has the story.

DES MOINES, Iowa ---- From corn-circled towns to the neighborhoods of Des Moines and other cities, Iowa is mulling a choice that will affect the nation.

"You stand up for me Monday night, I will stand up and fight for you," Democratic presidential candidate Hillary Clinton said.

"It's going to be a very, very close election," Democratic presidential candidate Bernie Sanders said.

Clinton and Sanders have mere hours to shape the decisions or adjust to something else that intervenes.

Like Clinton's e-mails.

Friday, the State Department labeled as top-secret 22 of the e-mail messages on the private account that she used when heading the agency.

Disclosing that information can cause "exceptionally grave" security damage.

Clinton says the emails weren't marked as classified at the time they were sent. A Clinton spokesman called it a case of over-classification run amok and asked for more emails to be publically released.

Republicans have pounced on the issue, but Sanders seemed to rule out attacking it months ago.

"People are sick and tired of hearing about your damn emails," he said to Clinton at a Democratic presidential debate Oct. 13.

And rumors of Sanders launching a last-minute ad on her Wall Street ties haven't come to pass so far.

Instead, he's banking on firing up the youth vote that catapulted President Obama ahead eight years ago.

"If we win, it will indicate that this country is ready for real significant change," Sanders said.

It’s easier said than done in a caucus.

"You're sitting there for three, four hours," said Bryan McQuide, a political science professor for Grand View University.

McQuide adds that Clinton is again banking on the more reliable older and rural vote, with a university rally at Grand View University thrown in to cut into Sanders's base.

Another wildcard is if supporters of former Maryland Gov. Martin O'Malley defect during caucuses. He's well behind in polls.

"In the caucus, you can change your vote during the party meeting," McQuide said. "There's speeches and people give speeches on behalf of a candidate and there's a time period where you have a chance to change your vote."

The professor's prediction: Clinton squeaks out a win in Iowa, but the e-mail controversy dogs her for months, making this a long haul for the Democratic nomination.