by Rick Pearson

DES MOINES -- Sunday marks the beginning of an important week in Iowa for the nation's Republican presidential contenders.

Starting the week with a 90-minute debate broadcast Sunday morning on ABC's This Week, it's likely that the sizable GOP field may be culled after the results of the Iowa Republican Party's straw poll in Ames on Saturday.

While the ABC debate features a full slate of candidates, two prominent candidates aren't taking part in the straw poll—former New York Mayor Rudy Giuliani and Arizona Sen. John McCain—leaving expectations for a high finish in the early balloting to former Massachusetts Gov. Mitt Romney.

Already, some of the so-called second tier contenders have indicated that without a top finish in the straw poll, they'll pull up stakes on their presidential aspirations.

That makes the debate on Sunday all the more important for the contenders to get their points across.

"Ask Mitt anything,'' his campaign forums invite. So the question this week is what sort of showing he will need in the ever-symbolic Iowa Straw Poll with neither Rudy Giuliani nor John McCain working the event in Ames to establish a foothold in the first caucus state.

And while Giuliani isn't competing in the straw poll, he is spending a lot of time early this week in the nation's first caucus state, with a full string of appearances across Iowa from shortly after the debate ends Sunday morning through Tuesday evening.

To be sure, the straw poll is a major fundraiser for the Iowa GOP as candidates bus their supporters to the Iowa State University campus in Ames, pay their $35 entry ticket, and ply them with food and entertainment.

But the event also provides an early indication of organizational support heading into the fall when caucus-goer recruitment goes into top gear for the Jan. 14 caucuses.

Giuliani's heavy schedule early in the week may be indicative of the need to show he's actively working the state while eschewing the straw poll.

State Sen. Mary Lundby of Marion, a co-chair of Giuliani's Iowa campaign and the retiring leader of the GOP's Senate minority, downplayed her candidate's decision not to play in the straw poll.

The straw poll results represent a "one-day bump" to a candidate, said the 22-year veteran of the legislative wars.

"The straw poll is far removed from the caucus. August to January is a long time," Lundby said. "The meat in the sandwich isn't the straw poll. It's the caucus and that's what you have to win."

Lundby also discounted any perceptions that Giuliani has mounted a drive-by campaign in the state while looking ahead to Feb. 5 and the host of states holding primaries and caucuses that day which might find his socially moderate positions more amenable.

"There's a strong tradition of having to do well in the Iowa caucuses to be successful," Lundby said. "We don't want to ignore Iowa in any shape or form. We're starting to ramp up the visits here. We're ramping up phone calls across the state.

Lundby said the campaign's caucus recruitment effort has gone beyond just contacting past caucus goers, but also is reaching out to people who have recently moved to the state or have never been old enough to take part.

The campaign is also offering undecided caucus goers a chance to meet Giuliani in person and ramping up a ground game based on having a pair of people in each precinct and working personal contacts rather than phone calls or automated calls.

"If you're not willing to sweat, you're not going to win the caucus," she said. "Iowans expect their contacts to be personal and I can tell you, the Giuliani campaign is making it."