Incumbent Democratic Gov. Jim Doyle had been running comfortably ahead of his Republican challenger, U.S. Rep. Mark Green, but the latest poll suggests a tightening race, with Green only six points behind. Liability issues have been an important factor in the race since Gov. Doyle vetoed four civil justice reform bills last January, including curbs on lead-paint and gun lawsuits, a product-liability bill, and a measure that would have moved Wisconsin's lenient expert-evidence standards toward a Daubert standard. Not long before that, Gov. Doyle vetoed a measure that would have limited medical malpractice recoveries, although he later signed a less restrictive measure.