Most of the attention heading into Saturday's Iowa straw poll is on Michele Bachmann and Tim Pawlenty, yet the lesser-known Republican candidates for president are working equally as hard to pull off a surprise.

And that might even be possible.

The Republican governor of Iowa, Terry Branstad, says the straw poll is wide open. He warns against buying into the conventional wisdom that there are any front-runners for the nonbinding vote.

The outcome of the straw poll on Saturday in Ames can indicate both the popularity of the candidates as well as which campaign has the strongest organization in Iowa, the state that launches the presidential nominating season.

Often, overlooked candidates like Herman Cain, Rick Santorum and Ron Paul focus for months on the quiet business of grass-roots organizing.

Republican presidential contender Tim Pawlenty has staked his political future on this weekend's Iowa straw poll.  He and his fellow Minnesota rival for the Republican nomination, Michelle Bachmann, sparred pointedly during a televised debate in Iowa on Thursday night. 

Pawlenty has devoted much of the past two months to the Hawkeye State, but that's also creating some problems for his campaign in New Hampshire.  Some say his New Hampshire operation, the most active early in the year, is paralyzed.  Already one member of Pawlenty's New Hampshire steering committee joined another campaign. Others are teetering. Pawlenty's scheduled to return to New Hampshire late next week.

Meanwhile, Texas Gov. Rick Perry is expected to officially announce his candidacy for the Republican nomination on Saturday.

Part of Perry's pitch is the Texas economy, which has fared better than most states during the nation's economic troubles.

But President Barack Obama's political team is taking an early swipe at Perry's record.  Obama senior political adviser David Axelrod says Texas benefited from booming oil prices and increased military spending on two wars.  He said Friday on CBS' "Early Show," "I don't think many people would attribute it to the leadership of the governor down there."

Axelrod also criticized the wider Republican field in Thursday night's debate, saying they were more interested in pledging allegiance to the tea party's anti-tax values than in helping middle-class Americans.