The heat in Ohio's competitive Senate race has been turned up as state Democrats challenge the Republican nominee's claims of transparency.

Republican nominee Josh Mandel spoke about his belief in transparency Wednesday during an event with the Pickaway County Chamber of Commerce, CirclevilleToday.com reported. Mandel, Ohio's state treasurer, was asked about disclosure requirements for campaign contributions during the event.

"I strongly believe in transparency. I think it’s an important component to our country and our political system," Mandel said. "I think over time -- my guess would be -- you’ll be seeing the Senate making strides to increase transparency."

Ohio Democratic Party spokesman Andrew Zucker said he believes that Mandel's record shows the opposite of transparency, pointing to actions Mandel has taken as state treasurer and within his Senate campaign. Mandel is challenging incumbent Sen. Sherrod Brown (D).

"The only thing Josh Mandel has been transparent about is his willingness to lie time and time again as he continues proving he's a do-or-say anything politician who simply can't be trusted," Zucker said in a statement.

Zucker points out several issues with Mandel's record of transparency, including missing 14 months of state Board of Deposit meetings that he chairs, his decision to decline requests for resumes of staffers, Mandel submitting a personal financial disclosure form six months after the deadline and his decision to decline to comment on various federal issues.

Mandel, a Tea Party favorite, has been under fire for several of the issues in recent months including the resumes and Board of Deposit meetings. Reviews of Mandel's state schedule had not indicated the board meetings and few other official appointments. Treasurer's office officials declined eight requests from state Democrats to release the resumes of various staffers hired by Mandel, at points saying the resumes were not in the office and that the resumes belonged to Mandel's transition fund and, therefore, were not public record.

The resumes were eventually released last month, following the ninth request.

The transparency debate comes just days after Crossroads GPS, a national advocacy group founded by Karl Rove, bought another $1.1 million in ads on Mandel's behalf in the race. Conservative groups have now spent $10.5 million on the Ohio race, while liberal leaning groups have spent $2.5 million.

During the event Wednesday, Mandel said he believes political attack ads will continue and decried "hyper-partisanship," saying that it leads to gridlock in Washington. He also pledged to serve two terms in office.

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