Former Gov. Mitt Romney of Massachusetts is so far ahead in spending and organization that the party’s other top tier hopefuls have dropped out of the Saturday event in Ames, The Washington Post reports.

Former New York Mayor Rudy Giuliani and Sen. John McCain of Arizona decided to forgo the Iowa straw poll after watching Romney assemble what amounts to a formidable force.

The GOP presidential primary candidate has a corps of 60 “super-volunteers” in Iowa who have been paid as much as $1,000 a month to talk him up plus a nearly $200,000 consultant to direct operations.

In addition, Romney has spent more than $2 million on television ads in the state.

Dave Roederer, who heads McCain’s campaign, says with so much money flowing in Iowa, it will be hard for Romney to attribute his win to voter sentiment.

The Post says officials with other campaigns have complained privately that some local party activists have said they felt compelled to back Romney because of the stipends he was offering.