The Ohio Election Commission is meeting Thursday for a preliminary hearing into whether an ad from the campaign of Rep. Zack Space (D-Ohio) contained false charges against Republican opponent Bob Gibbs.

The Gibbs campaign filed a complaint before the commission after a Space ad went up accusing the Republican of supporting tax increases and voting to raise his own pay as a member of the State Legislature. Gibbs called the charges a lie.

Philip Richter, the commission's executive director, said he anticipates that lawyers representing both campaigns will appear before a three-person panel in Columbus to present their case. But the Space campaign would not confirm that anyone representing it would appear.

Space campaign manager Danny Friedman said the campaign stands behind the content of the ad, but declined to offer further comment on the matter, pointing to an earlier statement.

"Our ad is completely accurate," Friedman said in the statement. "When Bob Gibbs supported the budget in 2003, he supported the largest tax increase in Ohio's history and a pay raise for himself and his fellow legislators. If supporting this pay increase wasn't bad enough, he authorized legislation to give special tax breaks for golf courses. This is the ugly truth Bob Gibbs doesn't want voters to know, but these are the facts." dug into the ad's content Tuesday and disputed its claim that Gibbs voted himself a pay raise.

The Gibbs campaign wants the ad pulled from the airwaves, but Richter said the commission doesn't actually have the authority to do that. If it were to conclude the ad contained factual inaccuracies, the strongest action it's likely to take is to issue a public reprimand.

"The elections commission will prove that Zack Space lied," said Gibbs spokeswoman Emily Pettigrew in an e-mail. "Bob Gibbs never voted himself a pay raise and has always voted for tax breaks for families."

Republicans are hopeful Gibbs can mount a serious challenge to Space, but the incumbent starts with a significant financial edge. Gibbs nearly drained his campaign coffers during a contested Republican primary.