For presidential campaign offices in Iowa, it’s the most wonderful time of the year. Or at least it’s the busiest. In a typical three hour shift, on...

For presidential campaign offices in Iowa, it's the most wonderful time of the year. Or at least it's the busiest.

In a typical three hour shift, one volunteer makes more than 100 calls to potential caucus-goers.

"We've been in here since August. It's a long haul, and this is the most intense week by far of any campaign I've ever been involved in," says Normal Bower, a volunteer for the Clinton campaign.

Just across town at the Bernie Sanders campaign headquarters, the feelings are mutual.

Volunteers work tirelessly to collect and assemble packets and fliers with candidate information. It's all to encourage people to get out and caucus for their favorite candidate.

"Bernie's the right choice because he's going to make the economy work for everybody and not just billionaires," says Chris Kelly, a Sanders campaign volunteer.

"Hillary Clinton is by far the most qualified person to be our next president," says Jane Artman-Andrews, a volunteer for the Clinton campaign.

Right now in Iowa, the democratic race is neck and neck. According to Real Clear Politics, right now, it's a virtual tie between the two candidates. But for the volunteers, their minds are already made.

"They'll pick the most qualified person, and that person is Hillary Clinton," says Artman-Andrews.