Saturday may well mark the end of Tommy Thompson's presidential aspirations. The former Wisconsin governor and Bush cabinet secretary barely registers, in the latest University of Iowa poll, heading into the Iowa Straw Poll in Ames. Radio Iowa News Director, O. Kay Henderson , says historically, the straw poll has narrowed the Republican field: "candidates who don't do very well drop out quickly thereafter." Henderson says despite visiting every Iowa county and probably spending more days in the state this year than any other candidate, Thompson has failed to light a fire with the state's Republican faithful. "The conventional wisdom is that the first person to drop out after the straw poll is likely to be Tommy Thompson," she says. Former Massachusetts Governor Mitt Romney appears the favorite among Iowa Republicans, with Rudy Guilianni, John McCain and Fred Thompson electing not to participate in the straw poll.