Scottie Mayfield speaks in this screenshot of a Chuck Fleischmann ad.

NASHVILLE - Republican U.S. Rep. Chuck Fleischmann's campaign is on the air with a new television ad in which his 2012 rival, Scott Mayfield, raises "trust" and "values" questions about the congressman's GOP primary opponent, Weston Wamp, over a secret-recording controversy last spring.

"While I was at home playing with my grandson, Weston Wamp showed up at my doorstep, uninvited, to argue politics and secretly recorded our conversation," says Mayfield, wearing his trademark bowtie, in the 30-second spot which began hitting local television sets today.

"Now he's asking for your trust to represent us in Washington?" Mayfield continues. "Those aren't East Tennessee values. We have a congressman we can trust, who's pro-life, endorsed by the NRA and not afraid to stand up to Obama."

The ad, appearing just two weeks from the Aug. 7 GOP primary, stems from a March incident, initially reported by the Times Free Press, in which Mayfield charged Wamp secretly recorded a conversation they had when Wamp came unexpectedly to his home to talk him out of supporting Fleischmann.

In 2012, Fleischmann, Mayfield and Wamp were in a fierce three-man GOP primary in the 3rd Congressional District as Fleischmann sought a second term. In 2014, Mayfield, a former executive at Mayfield Dairy, is backing Fleischmann.

Wamp has defended the recording, saying he was "concerned and still am concerned that Mr. Mayfield may have been a victim of the lies, threats and misinformation that has been spread from Congressman Fleischmann, and his cronies, since I entered the race in January."

"Scottie Mayfield says he thought the conversation was private and it was, until he made it public today. I intended to keep it private."