01/03/2012 02:54 EST | Updated 03/04/2012 05:12 EST

Republican hopefuls make last pitch in Iowa

Iowa Valley High School seniors Mitch Monahan and Jared Johnson, who gathered in the gymnasium Tuesday morning to see some Republican nominees make their last-day pitch, still don’t know who they will support at their local caucus.

"Not really sure yet. I mean it depends. I wanna see who shares the same opinions. I'm not just going to vote for somebody because my parents are," said Monahan, who, at 17, is eligible to vote.

"I’m not sure yet. I kinda like Ron Paul, and [Texas Gov. Rick] Perry are my favourites," Johnson added.

As part of a "Rock the Caucus" initiative, about 800 school seniors filled the gymnasium rafters to see the candidates, hours before Iowa Republicans head out to schools, firehalls, community centres and libraries to vote in the 1,774 precinct caucuses and choose delegates for the nomination convention.

According to recent polls, the race has come down to three candidates — with former Massachusetts governor Mitt Romney and Texas congressman Ron Paul in a dead heat — but former Pennsylvania senator Rick Santorum enjoying a last-minute surge of support.

However, undecided voters — a recent Des Moines Register poll suggested their numbers are hovering around 40 per cent — may not make up their mind until Tuesday evening.

Santorum, joined by his family, told students "this is a big moment" and urged them to vote.

Paul received the biggest ovation from the student crowd — not surprising since his campaign has been fuelled by the youth vote.

“I don’t know the exact reason for it,” Paul said. "One of the most common answers that I get is that I endorse the constitution and defend the constitution constantly in Washington and that’s very appealing to young people.”

The “Romney boys” — four of his five sons — also took the stage to advocate on the behalf of their father, who had attended a campaign rally earlier in Des Moines.

Minnesota congresswoman Michele Bachmann, whose campaign appears to have stagnated, led off the school event, shouting out a "Go Tigers" to the receptive students.

"Tonight, I'm urging all of you to come out to the caucuses. Tonight is your night to weigh in and make a difference," Bachmann said.

Perry was holding a number of campaign events in Des Moines, while former House speaker Newt Gingrich stumped in the eastern part of the state.

Tuesday night's vote is the official kickoff to the presidential primary season, with the next big contests set for New Hampshire and South Carolina. The goal for the Republicans is to unseat President Barack Obama.