PHOENIX — Attorney General Tom Horne goes before an administrative law judge Monday to defend himself against charges that he violated state campaign-finance laws in his 2010 election.

Horne is facing a complaint by Yavapai County Attorney Sheila Polk that he illegally coordinated with what was supposed to be an independent campaign finance committee on a last-minute commercial that may have helped him beat Democrat Felecia Rotellini.

But Mike Kimerer, Horne’s attorney, calls the evidence being presented “circumstantial and coincidental.” He said there’s a legitimate explanation for everything that Polk asserts shows laws were broken.

The case stems from a $513,340 TV commercial produced and paid for by Business Leaders for Arizona. That committee, formed before the general election, was being run by Kathleen Winn, who worked for Horne while he was state school superintendent and worked on his 2010 GOP primary race.

Winn now works for Horne in the Attorney General’s Office.

Polk, working with interviews, phone records and emails gathered by the FBI, said there is evidence of coordination between Horne and Winn about the commercial.

That, she said, made the commercial effectively an “in-kind” contribution to Horne’s campaign.

If the committee were acting under Horne’s direction, it would be subject to the $840 limit on donations from any one source.

Polk ordered Horne and Winn to refund all donations above that limit, close to $500,000, including an extra $349,160 from the Republican State Leadership Committee. They refused, forcing the hearing before Administrative Law Judge Tammy Eigenheer.

Polk’s case is based on emails between Winn and campaign consultant Brian Murray, coupled with the timing of those emails and phone calls between Winn and Horne.

Polk, in her complaint, said that provides “convincing proof Horne and Winn coordinated’ on the anti-Rotellini ad.

Kimerer said there’s a big hole in Polk’s case.

“They have no direct proof that there’s conversations going on about coordination,” he said.

“I think it stretches the imagination, regardless of the sequence of the calls or the timing, that you just automatically have to assume they’re talking about this particular ad,” Kimerer continued. More likely, they were discussing a real estate deal Kimerer said Winn was helping Horne to close.