By Jamie Coomarasamy
BBC News, Iowa
Mitt Romney may have to win over grassroots activists in Iowa
As the first US state to choose its presidential nominees, Iowa has always been a place of pilgrimage for would-be White House occupants.
This year, with such large and contested Democratic and Republican fields, pilgrims are virtually tripping over each other as they battle for the affections of the Iowa party faithful, ahead of next January's caucuses.
In April alone, candidates made about 70 visits to the state and attended hundreds of different events - as well as holding down day jobs in Congress and at governors' mansions.
Local campaign teams have been up and running - and in some cases, they have been for a while.
Barack Obama, to take an example, has 50 staff working in Iowa already. Those record fundraising totals for the first quarter of 2007 may not look as big as all that, before long.
David Yepson of the Des Moines Register has been covering Presidential election campaigns in Iowa since the mid-seventies.
He says he has never seen anything like it.
"The campaigns in Iowa now are operating like they used to two or three weeks before an election," he said.
"The pace, the energy level, the candidate activity, the staff activity - it's at a fever pitch. The question for me is, how do they sustain this pace? How do they hope to sustain interest by American voters?"
It's a question that the campaigns themselves are probably asking in private - even as they talk up their candidates' energy.
In some ways, keeping up the interest level may be easier for the Republicans, because they have more to prove to their grassroots.
At least, that is true of those in Boone County, north of Des Moines, who I met at their monthly meeting in a room above the local public library.
These committed grassroots activists, who will vote in the caucuses and set the tone for the presidential race are - in general - from the socially conservative wing of the party.
For them, all three frontrunners - Arizona Senator John McCain, former New York Mayor Rudy Giuliani and former Massachusetts Governor Mitt Romney - are problematic, whether it's because they have been married more than once or, in the case of Romney, because they are of a different, Mormon faith.
Marti Streeter, the co-chair of the Boone County Republicans, said she could not vote for any of the three leading candidates - and if Mr Giuliani were the nominee, she would resign from the party.
Mr McCain is among the contenders to have visited Iowa recently
Others, though, were less categorical. Tom Rosenbaum was among those who gave the former New York mayor high marks for his performance on 11 September 2001.
However, Mr Giuliani's three marriages prompted another activist, Matthew Murch, to say "if the choice was between Giuliani and Hillary, I'd write in Mickey Mouse as my candidate".
Senator McCain was accused of changing his mind on issues, but the candidate with most to do in Boone County seems to be Mitt Romney.
Unprompted, a majority of those in the room stated categorically that they would never vote for a Mormon.
"We are a Christian nation," Anne Darby said, "and we should have a Christian president."
The debates will give the big three - as well as the seven lesser-known candidates currently in the Republican race - the chance to shatter preconceptions and appear presidential.
Jim Gilmore formally announced his candidacy in Iowa
But, according to David Yepson, the debates threaten pitfalls as well.
"There's a huge gaffe potential in this campaign, because it's so long. Under the white-hot light of scrutiny, tired candidates can make little errors that will be blown out of proportion.
"I think you'll find several candidates who won't survive the debate marathon."
And they seem to realise it. None of the Republican candidates has been to Iowa this week.
They have been too busy studying their notes and polishing their sound bites in time for the first live debate in California.