Updated

Searching for a Senate upset on Nov. 2, Democrats are putting fresh money down in Kentucky in hopes of denying Republican Sen. Jim Bunning (search) a second term.

Several sources, speaking on condition of anonymity, said Thursday the Democratic Senatorial Campaign Committee (search) had purchased more than $800,000 worth of television time to air commercials designed to help Democratic candidate Dan Mongiardo (search). The commercials will run through the election.

Bunning holds a huge financial advantage over his rival, a physician and state senator. But even Republicans concede privately that a once formidable lead has dwindled under the weight of a series of controversial comments and curious actions.

At various points in the campaign, Bunning has said his wife was "black and blue" after Mongiardo's staff assaulted her at a summer picnic — and compared his rival's appearance to one of Saddam Hussein's sons. Mongiardo denied the first charge, and Bunning apologized for the second comment.

Recently, Bunning did not appear in Kentucky for a scheduled campaign debate, deciding instead to participate via remote hookup from Washington.

On Wednesday, Bunning opened a late-campaign trip around the state and accused his rival of spreading rumors about his mental health.

"The rumors that have been spread by my opponent about my health are disgusting," Bunning said during a campaign stop here. "People who know me know the truth."

Mongiardo dismissed the charge as "just another absurd comment," and questioned what he called his opponent's "bizarre conduct."