Republican Stan Wise declined the club's invitation for the Oct. 21 event. His only comment when asked was, "I regretted."
The club invited Wise and his opponent, Libertarian David Staples, who has already accepted.
"I'm certainly not surprised that he would choose to not participate in a debate. He has nothing to gain," said Staples. "He rarely makes himself available to constituents, as he appears to have a disdain for them unless they're funding his campaign, so why would this be any different?"
Wise may have little risk of hurting his election chances by not showing up as a Republican incumbent, according to Georgia State University political science Professor Steve Anthony, a former Democratic operative. But incumbent presidents debate challengers, and Wise is going to gain a reputation for ducking out.
"It certainly should be fair game for part of the description that everyone uses to describe him," Anthony said. "An elected official has an obligation to meet the public."
In keeping with the club's long-standing practice when candidates decline, an empty lectern will show their absence, and the remaining candidates will field questions from a panel of journalists from across the state.
Over the decades, the club's debates are often the most spirited and usually the only ones broadcast statewide on Georgia Public Broadcasting. The format also permits the candidates to ask each other questions, which often gets simmering campaign issues to the surface.
This summer, Wise also declined the club's primary debate. The club read a statement from him saying recent eye surgery prevented him from participating then.
There are only two statewide races this year, both for seats on the Public Service Commission that regulates utilities. With the commission overseeing the construction of the country's first two commercial, nuclear reactors in thirty years at Plant Vogtle and with Georgia Power's electricity bills rising as a result, there are plenty of issues for the candidates to debate.
All of the candidates for the other seat on the commission have agreed to participate, including incumbent Republican Chuck Eaton, Democrat Steve Oppenheimer and Libertarian Brad Ploeger.
The same night, the club is hosting debates for the 9th and 12th congressional districts and a forum on the charter-school amendment to the constitution that's on this fall's ballot.
In the 12th, incumbent Democrat John Barrow has accepted the club's invitation, but Republican challenger Lee Anderson declined. Anderson has received considerable criticism for his decision in what is a closely watched race by political observers from across the country since Barrow is the only white Democrat from the deep South.